Everything about blood vessels: types, classifications, characteristics, meaning. Large human vessels Which vessels consist of three layers of tissue

Blood vessels get their name depending on the organ they supply (renal artery, splenic vein), the place of their origin from a larger vessel (superior mesenteric artery, inferior mesenteric artery), bone to which they are adjacent (ulnar artery), direction (medial artery surrounding the thigh), depth (superficial or deep artery), Many small arteries are called branches, and veins are called tributaries.

Arteries . Depending on the area of ​​branching, the arteries are divided into parietal (parietal), which supply blood to the walls of the body, and visceral (internal), which supply blood to the internal organs. Before an artery enters an organ, it is called organ; after entering an organ, it is called intraorgan. The latter branches within the organ and supplies its individual structural elements.

Each artery breaks down into smaller vessels. With the main type of branching, lateral branches arise from the main trunk - the main artery, the diameter of which gradually decreases. With the tree-like type of branching, the artery immediately after its origin is divided into two or several terminal branches, resembling the crown of a tree.

The artery wall consists of three membranes: inner, middle and outer. The inner shell is formed by the endothelium, subendothelial layer and internal elastic membrane. Endotheliocytes line the lumen of the vessel. They are elongated along its longitudinal axis and have slightly tortuous boundaries. The subendothelial layer consists of thin elastic and collagen fibers and poorly differentiated connective tissue cells. On the outside there is an internal elastic membrane. The medial layer of the artery consists of spirally arranged myocytes, between which there is a small amount of collagen and elastic fibers, and an outer elastic membrane formed by intertwining elastic fibers. The outer shell consists of loose fibrous unformed connective tissue containing elastic and collagen fibers.

Depending on the development of the various layers of the artery wall, they are divided into vessels of the muscular, mixed (muscle-elastic) and elastic types. In the walls of arteries of the muscular type, which have a small diameter, the middle membrane is well developed. The myocytes of the middle lining of the walls of muscular arteries regulate blood flow to organs and tissues through their contractions. As the diameter of the arteries decreases, all the membranes of the walls become thinner, and the thickness of the subendothelial layer and internal elastic membrane decreases.

Fig. 102. Scheme of the structure of the wall of an artery (A) and vein (B) of the muscular type of medium caliber / -inner membrane: 1-endothelium. 2- basement membrane, 3- subendothelial layer, 4- internal elastic membrane; // - tunica media and in it: 5- myocytes, b-elastic fibers, 7-collagen fibers; /// - outer shell and in it: 8- outer elastic membrane, 9- fibrous (loose) connective tissue, 10- blood vessels

The number of myocytes and elastic fibers in the middle shell gradually decreases. The number of elastic fibers in the outer shell decreases, and the outer elastic membrane disappears.

The thinnest arteries of the muscular type - arterioles - have a diameter of less than 10 microns and pass into capillaries. The walls of arterioles lack an internal elastic membrane. The middle shell is formed by individual myocytes, which have a spiral direction, between which there is a small number of elastic fibers. The outer elastic membrane is expressed only in the walls of the largest arterioles and is absent in small ones. The outer shell contains elastic and collagen fibers. Arterioles regulate blood flow into the capillary system. To the arteries mixed type These include large-caliber arteries such as the carotid and subclavian. In the middle shell of their walls there is approximately an equal number of elastic fibers and myocytes. The internal elastic membrane is thick and durable. In the outer shell of the walls of mixed-type arteries, two layers can be distinguished: the inner layer, containing individual bundles of myocytes, and the outer layer, consisting mainly of longitudinally and obliquely located bundles of collagen and elastic fibers. The elastic type arteries expose the aorta and pulmonary trunk, into which blood flows under high pressure at high speed from the heart. ; On the walls of these vessels, the inner lining is thicker; the internal elastic membrane is represented by a dense plexus of thin elastic fibers. The middle shell is formed by elastic membranes located concentrically, between which myocytes lie. The outer shell is thin. In children, the diameter of the arteries is relatively larger than in adults. In a newborn, the arteries are predominantly of the elastic type; their walls contain a lot of elastic tissue. The arteries of the muscle phlegm are not yet developed.

The distal part of the cardiovascular system is the microcirculatory bed (Fig. 103), which ensures the interaction of blood and tissues. The microcirculatory bed begins with the smallest arterial vessel - the arteriole and ends with the venule.

The artery wall contains only one row of myocytes. Precapillaries extend from the arteriole, at the beginning of which there are smooth muscle precapillary sphincters that regulate blood flow. In the walls of precapillaries, unlike capillaries, single myocytes lie on top of the endothelium. True capillaries begin from them. True capillaries flow into postcapillaries (postcapillary venules). Postcapillaries are formed from the fusion of two or more capillaries. They have a thin adventitial membrane, their walls are extensible and have high permeability. As the postcapillaries merge, venules are formed. Their caliber varies widely and under normal conditions is 25-50 microns. Venules merge into veins. Within the microcirculatory bed there are vessels for the direct transfer of blood from the arteriole to the venule-arteriolo-venular anastomoses, in the walls of which there are myocytes that regulate blood discharge. The microvasculature also includes lymphatic capillaries.

Typically, an arterial type vessel (arteriole) approaches the capillary network, and a venule emerges from it. In some organs (kidney, liver) there is a deviation from this rule. Thus, an arteriole (afferent vessel) approaches the glomerulus of the renal corpuscle. An arteriole (an efferent vessel) also leaves the glomerulus. 8 of the liver, the capillary network is located between the afferent (interlobular) and efferent (central) veins. A capillary network inserted between two vessels of the same type (arteries, veins) is called a miraculous network.

Capillaries . Blood capillaries (hemocapillaries) have walls formed by one layer of flattened endothelial cells - endothelial cells, a continuous or discontinuous basement membrane and rare pericapillary cells - pericytes, or Rouget cells.

Endotheliocytes lie on the basement membrane (basal layer), which surrounds the blood capillary on all sides. The basal layer consists of fibrils intertwined with each other and an amorphous substance. Outside the basal layer lie Rouget cells, which are elongated multi-processed cells located along the long axis of the capillaries. It should be emphasized that each endothelial cell is in contact with pericyte processes. In turn, each pericyte is approached by the ending of the axon of the sympathetic neuron, which, as it were, extends into its plasmalemma. The pericyte transmits an impulse to the endothelial cell, causing the endothelial cell to swell or lose fluid. This leads to periodic changes in the lumen of the capillary.

The cytoplasm of endothelial cells may have pores, or fenestrae (porous endotheliocyte). Non-cellular component - the basal layer can be solid, absent or porous. Depending on this, three types of capillaries are distinguished:

1. Capillaries with continuous endothelium and basal layer. Such capillaries are located in the skin; striated (striated) muscles, including the myocardium, and non-striated (smooth); cerebral cortex.

2. Fenestrated capillaries, in which some areas of endothelial cells are thinned.

3. Sinusoidal capillaries have a large lumen, up to 10 microns. Their endothelial cells contain mora, and the basement membrane is partially absent (discontinuous). Such capillaries are located in the liver, spleen, and bone marrow.

Postcapillary venules with a diameter of 100-300 µm, which are the final link of the microvasculature, flow into collecting venules (with a diameter of 100-300 µm). which, merging with each other, become larger. The structure of postcapillary venules over a considerable extent is similar to the structure of the walls of capillaries, they only have a wider lumen and a larger number of pericytes. The collecting venules have an outer membrane formed by collagen fibers and fibroblasts. In the middle shell of the wall of larger venules there are I-2 layers of smooth muscle cells, the number of their layers increases in the collecting foams,

Vienna . The vein wall also consists of three membranes. There are two types of veins: amuscular and muscular types. In amuscular veins, a basement membrane is adjacent to the endothelium on the outside, behind which there is a thin layer of loose fibrous connective tissue. Veins of the non-muscular type include hard and soft veins. meninges, retina, bones, spleen and placenta. They are tightly fused with the walls of the organs and therefore do not collapse.

Veins of the muscular type have a well-defined muscular layer formed by circularly arranged bundles of myocytes separated by layers of fibrous connective tissue. There is no outer elastic membrane. The outer connective tissue membrane is well developed. The inner lining of most medium and some large veins has valves (Fig. 104). Superior vena cava, brachiocephalic, common iliac, veins of the heart, lungs. adrenal glands, brain and their membranes, parenchymal organs do not have valves. The valves are thin folds of the inner membrane, consisting of fibrous connective tissue, covered on both sides with endothelial cells. They allow blood to pass only towards the heart, prevent the reverse flow of blood in the veins and protect the heart from unnecessary energy expenditure to overcome oscillatory movements blood constantly appearing in the veins. The venous sinuses of the dura mater, which drain blood from the brain, have non-collapsing walls that ensure unimpeded flow of blood from the cranial cavity into the extracranial veins (internal jugular).

The total number of veins is greater than the number of arteries, and the total size of the venous bed exceeds the arterial one. The speed of blood flow in the veins is less than in the arteries; in the veins of the torso and lower extremities, blood flows against gravity. The names of many deep veins of the extremities are similar to the names of the arteries that they accompany in pairs - companion veins (ulnar artery - ulnar veins, radial artery - radial veins).

Most veins located in body cavities are single. The unpaired deep veins are the internal jugular, subclavian, axillary, iliac (common, external and internal), femoral and some others. Superficial veins are connected to deep veins with the help of perforating veins, which act as anastomoses. Neighboring veins are also interconnected by numerous anastomoses, collectively forming venous plexuses, which are well expressed on the surface or in the walls of some internal organs ( bladder, rectum).

The superior and inferior vena cava of the greater circulation drain into the heart. The system of the inferior hollow foam includes the portal vein and its tributaries. The roundabout flow of blood also occurs through collateral veins, but through them the blood flows out and bypasses the main path. The tributaries of one large (main) vein are connected to each other by intrasystemic venous anastomoses. Venous anastomoses are more common and better developed than arterial anastomoses.

The small, or pulmonary, circle of blood circulation begins in the right ventricle of the heart, from where the pulmonary trunk emerges, which is divided into the right and left pulmonary arteries, and the latter branch in the lungs into arteries that turn into capillaries. In the capillary networks entwining the alveoli, the blood gives off carbon dioxide and enriched with oxygen. Oxygen-enriched arterial blood flows from the capillaries into the veins, which, merging into four pulmonary veins (two on each side), flow into the left atrium, where the pulmonary (pulmonary) circulation ends.

The systemic, or bodily, circulation serves to deliver nutrients and oxygen to all organs and tissues of the body. It begins in the left ventricle of the heart, where arterial blood flows from the left atrium. The aorta emerges from the left ventricle, from which arteries extend to all organs and tissues of the body and branch in their thickness up to the arterioles and capillaries. The latter pass into venules and then into veins. Through the walls of capillaries, metabolism and gas exchange occurs between the blood and body tissues. The arterial crawl flowing in the capillaries breaks off nutrients and oxygen and receives metabolic products and carbon dioxide. Bens stick together into two large trunks - the superior and inferior vena cava, which flow into right atrium the heart, where the systemic circulation ends. In addition to the great circle, there is a third (cardiac) circle of blood circulation, serving the heart itself. It begins with the coronary arteries emerging from the aorta and ends with the veins of the heart. The latter stick together into the coronary sinus, which flows into the right atrium, and the remaining smallest veins open directly into the cavity of the right atrium and ventricle.

The course of the arteries and the blood supply to various organs depend on their structure, function and development and are subject to a number of laws. Large arteries are located according to the skeleton and nervous system. Thus, the aorta lies along the spinal column. On the limbs of the bone there is one main artery.

The arteries go to the corresponding organs along the shortest path, that is, approximately along a straight line connecting the main trunk with the organ. Therefore, each artery supplies blood to nearby organs. If an organ moves during the prenatal period, the artery, lengthening, follows it to the place of its final location (for example, diaphragm, testicle). The arteries are located on the shorter flexor surfaces of the body. Articular arterial networks are formed around the joints. Protection from damage and compression is provided by the bones of the skeleton, various grooves and channels formed by bones, mice, and fascia.

Arteries enter organs through the gate located on their bent medial or inner surface facing the source of blood supply. Moreover, the diameter of the arteries and the nature of their branching depend on the size and functions of the organ.

Blood vessels are a closed system of branched tubes of different diameters that are part of the systemic and pulmonary circulation. This system distinguishes: arteries, through which blood flows from the heart to organs and tissues, veins- through them the blood returns to the heart, and the complex of blood vessels microvasculature, providing, along with the transport function, the exchange of substances between the blood and surrounding tissues.

Blood vessels are developing from mesenchyme. In embryogenesis, the earliest period is characterized by the appearance of numerous cellular accumulations of mesenchyme in the wall of the yolk sac - blood islands. Inside the islet, blood cells form and a cavity is formed, and the cells located along the periphery become flat, connect with each other using cell contacts and form the endothelial lining of the resulting tube. As they form, such primary blood tubes interconnect and form a capillary network. The surrounding mesenchymal cells develop into pericytes, smooth muscle cells, and adventitial cells. In the body of the embryo, blood capillaries are formed from mesenchymal cells around slit-like spaces filled tissue fluid. When blood flow through the vessels increases, these cells become endothelial, and elements of the middle and outer membrane are formed from the surrounding mesenchyme.

The vascular system has a very large plasticity. First of all, there is significant variability in the density of the vascular network, since depending on the needs of the organ for nutrients and oxygen, the amount of blood brought to it varies widely. Changes in blood flow speed and blood pressure lead to the formation of new vessels and the restructuring of existing vessels. There is a transformation of a small vessel into a larger one with characteristic features of the structure of its wall. The greatest changes occur in the vascular system with the development of roundabout, or collateral, circulation.

Arteries and veins are built according to a single plan - three membranes are distinguished in their walls: internal (tunica intima), middle (tunica media) and external (tunica adventicia). However, the degree of development of these membranes, their thickness and tissue composition are closely related to the function performed by the vessel and hemodynamic conditions (blood pressure and blood flow velocity), which are not the same in different parts of the vascular bed.

Arteries. According to the structure of the walls, arteries of the muscular, muscular-elastic and elastic types are distinguished.

To elastic arteries include the aorta and pulmonary artery. In accordance with the high hydrostatic pressure (up to 200 mm Hg) created by the pumping activity of the ventricles of the heart, and the high speed of blood flow (0.5 - 1 m/s), these vessels have pronounced elastic properties, which ensure the strength of the wall when stretched and returning to its original position, and also contribute to the transformation of pulsating blood flow into a constant continuous one. The wall of elastic-type arteries is distinguished by its considerable thickness and the presence of a large number of elastic elements in the composition of all membranes.

Inner shell consists of two layers - endothelial and subendothelial. Endothelial cells that form a continuous internal lining have different sizes and shapes and contain one or more nuclei. Their cytoplasm contains few organelles and many microfilaments. Beneath the endothelium is the basement membrane. The subendothelial layer consists of loose, fine-fibrous connective tissue, which, along with a network of elastic fibers, contains poorly differentiated stellate-shaped cells, macrophages, and smooth muscle cells. In the amorphous substance of this layer, which has great value to nourish the wall, it contains a significant amount of glycosaminoglycans. When the wall is damaged and a pathological process (atherosclerosis) develops, lipids (cholesterol and its esters) accumulate in the subendothelial layer. The cellular elements of the subendothelial layer play an important role in wall regeneration. At the border with the tunica media there is a dense network of elastic fibers.

Middle shell consists of numerous elastic fenestrated membranes, between which obliquely oriented bundles of smooth muscle cells are located. Through the windows (fenestrae) of the membranes, intrawall transport of substances necessary to nourish the cells of the wall occurs. Both membranes and cells are smooth muscle tissue surrounded by a network of elastic fibers that, together with the fibers of the inner and outer shells, form a single frame that provides. high wall elasticity.

The outer shell is formed by connective tissue, which is dominated by bundles of collagen fibers oriented longitudinally. In this shell, vessels are located and branch, providing nutrition to both the outer shell and the outer zones of the middle shell.

Muscular arteries. Arteries of this type of different caliber include most of the arteries that deliver and regulate blood flow to various parts and organs of the body (brachial, femoral, splenic, etc.). Upon microscopic examination, the elements of all three shells are clearly visible in the wall (Fig. 5).

Inner shell consists of three layers: endothelial, subendothelial and internal elastic membrane. The endothelium has the appearance of a thin plate, consisting of cells elongated along the vessel with oval nuclei protruding into the lumen. The subendothelial layer is more developed in large-diameter arteries and consists of stellate or spindle-shaped cells, thin elastic fibers and an amorphous substance containing glycosaminoglycans. On the border with the middle shell lies internal elastic membrane, clearly visible on preparations in the form of a shiny, light pink, eosin-colored wavy stripe. This membrane is permeated with numerous holes that are important for the transport of substances.

Middle shell is built predominantly from smooth muscle tissue, the bundles of cells of which run in a spiral, however, when the position of the arterial wall changes (stretching), the location of the muscle cells can change. Contraction of the tunica media muscle tissue is important in regulating blood flow to organs and tissues according to their needs and maintaining blood pressure. Between the bundles of muscle tissue cells there is a network of elastic fibers, which, together with the elastic fibers of the subendothelial layer and the outer shell, form a single elastic frame that gives the wall elasticity when it is compressed. At the border with the outer shell in large arteries of the muscular type there is an outer elastic membrane, consisting of a dense plexus of longitudinally oriented elastic fibers. In smaller arteries this membrane is not expressed.

Outer shell consists of connective tissue in which collagen fibers and networks of elastic fibers are elongated in the longitudinal direction. Between the fibers there are cells, mainly fibrocytes. The outer shell contains nerve fibers and small blood vessels that supply the outer layers of the artery wall.

Rice. 5. Scheme of the structure of the wall of an artery (A) and vein (B) of the muscular type:

1 - inner shell; 2 - middle shell; 3 - outer shell; a - endothelium; b - internal elastic membrane; c - nuclei of smooth muscle tissue cells in the middle shell; d - nuclei of adventitia connective tissue cells; d - vessels of blood vessels.

Arteries of the muscular-elastic type According to the structure of the wall, they occupy an intermediate position between arteries of elastic and muscular types. In the middle shell, spirally oriented smooth muscle tissue, elastic plates and a network of elastic fibers are developed in equal quantities.

Vessels of the microvasculature. At the site of the transition of the arterial to venous bed in organs and tissues, a dense network of small precapillary, capillary and postcapillary vessels is formed. This complex of small vessels, which provides blood supply to organs, transvascular exchange and tissue homeostasis, is collectively called the microvasculature. It consists of various arterioles, capillaries, venules and arteriole-venular anastomoses (Fig. 6).

R
is.6. Diagram of microvasculature vessels:

1 - arteriole; 2 - venule; 3 - capillary network; 4 - arteriolo-venular anastomosis

Arterioles. As the diameter of muscular arteries decreases, all the membranes become thinner and they turn into arterioles - vessels with a diameter of less than 100 microns. Their inner shell consists of endothelium located on the basement membrane and individual cells of the subendothelial layer. Some arterioles may have a very thin internal elastic membrane. The tunica media contains one row of spirally arranged smooth muscle cells. In the wall of the terminal arterioles, from which the capillaries branch, smooth muscle cells do not form a continuous row, but are located separately. This precapillary arterioles. However, at the site of the branch from the arteriole, the capillary is surrounded by a significant number of smooth muscle cells, which form a kind of precapillary sphincter. Due to changes in the tone of such sphincters, blood flow in the capillaries of the corresponding area of ​​​​tissue or organ is regulated. There are elastic fibers between muscle cells. The outer shell contains individual adventitial cells and collagen fibers.

Capillaries- the most important elements of the microvasculature, in which the exchange of gases and various substances takes place between the blood and surrounding tissues. In most organs, branching structures are formed between arterioles and venules. capillary networks located in loose connective tissue. The density of the capillary network in different organs can be different. The more intense the metabolism in an organ, the denser the network of its capillaries. The most developed network of capillaries is in the gray matter of the nervous system, in the internal secretion organs, the myocardium of the heart, and around the pulmonary alveoli. In skeletal muscles, tendons, and nerve trunks, capillary networks are oriented longitudinally.

The capillary network is constantly in a state of restructuring. In organs and tissues, a significant number of capillaries do not function. Only blood plasma circulates in their greatly reduced cavity ( plasma capillaries). The number of open capillaries increases with the intensification of the organ's work.

Capillary networks are also found between vessels of the same name, for example, venous capillary networks in the liver lobules and adenohypophysis, arterial ones in the renal glomeruli. In addition to forming branched networks, capillaries can take the form of a capillary loop (in the papillary layer of the dermis) or form glomeruli (choroid glomeruli of the kidneys).

Capillaries are the narrowest vascular tubes. Their caliber on average corresponds to the diameter of a red blood cell (7-8 microns), however, depending on functional state and organ specialization, the diameter of the capillaries can be different. Narrow capillaries (diameter 4 - 5 microns) in the myocardium. Special sinusoidal capillaries with a wide lumen (30 microns or more) in the liver lobules, spleen, red bone marrow, and internal secretion organs.

Wall blood capillaries consists of several structural elements. The internal lining is formed by a layer of endothelial cells located on the basement membrane, the latter containing cells - pericytes. Around basement membrane adventitial cells and reticular fibers are located (Fig. 7).

Fig.7. Scheme of the ultrastructural organization of the wall of a blood capillary with a continuous endothelial lining:

1 - endotheliocyte: 2 - basement membrane; 3 - pericyte; 4 - pinocytotic microbubbles; 5 - contact zone between endothelial cells (Fig. Kozlov).

Flat endothelial cells elongated along the length of the capillary and have very thin (less than 0.1 μm) peripheral anucleate areas. Therefore, with light microscopy of a cross section of a vessel, only the area where the nucleus is located, 3-5 µm thick, is visible. The nuclei of endothelial cells are often oval in shape and contain condensed chromatin, concentrated near the nuclear membrane, which, as a rule, has uneven contours. In the cytoplasm, the bulk of organelles are located in the perinuclear region. The inner surface of endothelial cells is uneven, the plasmalemma forms microvilli, protrusions and valve-like structures of different shapes and heights. The latter are especially characteristic of the venous section of the capillaries. Along the inner and outer surfaces of endothelial cells there are numerous pinocytosis vesicles, indicating intensive absorption and transfer of substances through the cytoplasm of these cells. Endothelial cells, due to their ability to quickly swell and then, releasing fluid, decrease in height, can change the size of the lumen of the capillary, which, in turn, affects the passage of blood cells through it. In addition, electron microscopy revealed microfilaments in the cytoplasm that determine the contractile properties of endothelial cells.

basement membrane, located under the endothelium, is detected by electron microscopy and represents a plate 30-35 nm thick, consisting of a network of thin fibrils containing type IV collagen and an amorphous component. The latter, along with proteins, contains hyaluronic acid, the polymerized or depolymerized state of which determines the selective permeability of capillaries. The basement membrane also provides elasticity and strength to the capillaries. In the cleavages of the basement membrane, special branched cells are found - pericytes. They cover the capillary with their processes and, penetrating the basement membrane, form contacts with endothelial cells.

In accordance with the structural features of the endothelial lining and basement membrane, three types of capillaries are distinguished. Most capillaries in organs and tissues belong to the first type ( general type capillaries). They are characterized by the presence of a continuous endothelial lining and basement membrane. In this continuous layer, the plasma membranes of neighboring endothelial cells are as close as possible and form connections like tight contacts, which are impenetrable to macromolecules. There are also other types of contacts when the edges of neighboring cells overlap each other like tiles or are connected by jagged surfaces. According to the length of the capillaries, narrower (5 - 7 µm) proximal (arteriolar) and wider (8 - 10 µm) distal (venular) parts are distinguished. In the cavity of the proximal part, the hydrostatic pressure is greater than the colloid-osmotic pressure created by proteins in the blood. As a result, the liquid is filtered behind the wall. In the distal part, the hydrostatic pressure becomes less than the colloid osmotic pressure, which causes the transition of water and substances dissolved in it from the surrounding tissue fluid into the blood. However, the output flow of fluid is greater than the input, and the excess fluid, as part of the tissue fluid of the connective tissue, enters the lymphatic system.

In some organs in which the processes of absorption and release of fluid intensively occur, as well as rapid transport of macromolecular substances into the blood, the endothelium of the capillaries has rounded submicroscopic openings with a diameter of 60-80 nm or rounded areas covered by a thin diaphragm (kidneys, internal secretion organs). This capillaries with fenestraes(Latin fenestrae - windows).

Capillaries of the third type - sinusoidal, are characterized by a large diameter of their lumen, the presence of wide gaps between endothelial cells and a discontinuous basement membrane. Capillaries of this type are found in the spleen and red bone marrow. Not only macromolecules, but also blood cells penetrate through their walls.

Venules- efferent section of the micropirculatory bed and initial link venous section of the vascular system. They collect blood from the capillary bed. The diameter of their lumen is wider than in capillaries (15-50 microns). In the wall of venules, as well as in capillaries, there is a layer of endothelial cells located on the basement membrane, as well as a more pronounced outer connective tissue membrane. In the walls of the venules, which turn into small veins, there are individual smooth muscle cells. IN postcapillary venules of the thymus, lymph nodes, the eldothelial lining is represented by tall endothelial cells that promote selective migration of lymphocytes during their recycling. Due to the thinness of their walls, slow blood flow and low blood pressure, a significant amount of blood can be deposited in the venules.

Arteriolo-venular anastomoses. In all organs, tubes have been found through which blood from arterioles can be sent directly to venules, bypassing the capillary network. There are especially many anastomoses in the dermis of the skin, in the auricle, and in the crest of birds, where they play a certain role in thermoregulation.

Structurally, true arteriolovenular anastomoses (shunts) are characterized by the presence in the wall of a significant number of longitudinally oriented bundles of smooth muscle cells located either in the subendothelial layer of the intima (Fig. 8) or in the inner zone of the tunica media. In some anastomoses, these cells acquire an epithelial-like appearance. Longitudinal muscle cells are also found in the outer shell. There are not only simple anastomoses in the form of single tubes, but also complex ones, consisting of several branches extending from one arteriole and surrounded by a common connective tissue capsule.

Fig.8. Arteriolo-venular anastomosis:

1 - endothelium; 2 - longitudinally located epithelioid-muscle cells; 3 - circularly located muscle cells of the middle shell; 4 - outer shell.

With the help of contractile mechanisms, anastomoses can reduce or completely close their lumen, as a result of which the flow of blood through them stops and blood enters the capillary network. Thanks to this, the organs receive blood depending on the need associated with their work. In addition, high arterial blood pressure is transmitted through anastomoses to the venous bed, thereby facilitating better blood movement in the veins. The role of anastomoses is significant in enriching venous blood with oxygen, as well as in regulating blood circulation during the development of pathological processes in organs.

Vienna- blood vessels through which blood from organs and tissues flows to the heart, into the right atrium. The exception is the pulmonary veins, which carry oxygen-rich blood from the lungs to the left atrium.

The wall of veins, like the wall of arteries, consists of three membranes: inner, middle and outer. However, the specific histological structure of these membranes in different veins is very diverse, which is associated with differences in their functioning and local (according to the location of the vein) blood circulation conditions. Most veins of the same diameter as arteries of the same name have a thinner wall and a wider lumen.

In accordance with the hemodynamic conditions - low blood pressure (15-20 mm Hg) and low blood flow velocity (about 10 mm / s) - the elastic elements in the vein wall are relatively poorly developed and there is a smaller amount of muscle tissue in the tunica media. These signs make it possible to change the configuration of the veins: when the blood supply is low, the walls of the veins become collapsed, and when the outflow of blood is difficult (for example, due to blockage), stretching of the wall and expansion of the veins easily occur.

Essential in the hemodynamics of venous vessels are valves located in such a way that, while allowing blood to flow towards the heart, they block the path for its reverse flow. The number of valves is greater in those veins in which blood flows in the direction opposite to gravity (for example, in the veins of the extremities).

According to the degree of development of muscle elements in the wall, veins of non-muscular and muscular types are distinguished.

Veins are of non-muscular type. To characteristic veins of this type include veins of bones, central veins of the hepatic lobules and trabecular veins of the spleen. The wall of these veins consists only of a layer of endothelial cells located on the basement membrane and an outer thin layer of fibrous connective tissue. With the participation of the latter, the wall fuses tightly with the surrounding tissues, as a result of which these veins are passive in the movement of blood through them and do not collapse. The muscleless veins of the meninges and retina, when filled with blood, can easily stretch, but at the same time, the blood, under the influence of its own gravity, easily flows into larger venous trunks.

Muscular veins. The wall of these veins, like the wall of arteries, consists of three membranes, but the boundaries between them are less distinct. The thickness of the muscular membrane in the wall of veins of different locations is not the same, which depends on whether the blood moves in them under the influence of gravity or against it. Based on this, muscular-type veins are divided into veins with weak, medium and strong development of muscle elements. The veins of the first type include the horizontally located veins of the upper body of the body and the veins of the digestive tract. The walls of such veins are thin; in their middle shell, smooth muscle tissue does not form a continuous layer, but is located in bundles, between which there are layers of loose connective tissue.

Veins with strong development of muscle elements include large veins of the limbs of animals, through which blood flows upward, against gravity (femoral, brachial, etc.). They are characterized by longitudinally located small bundles of smooth muscle cells in the subendothelial layer of the intima and well-developed bundles of this tissue in the outer membrane. Contraction of the smooth muscle tissue of the outer and inner membranes leads to the formation of transverse folds of the vein wall, which prevents reverse blood flow.

The tunica media contains circularly arranged bundles of smooth muscle cells, the contractions of which help move blood to the heart. In the veins of the extremities there are valves, which are thin folds formed by the endothelium and subendothelial layer. The basis of the valve is fibrous connective tissue, which at the base of the valve leaflets may contain a number of smooth muscle cells. The valves also prevent the backflow of venous blood. The suction action is essential for the movement of blood in the veins. chest during inspiration and contraction of the skeletal muscle tissue surrounding the venous vessels.

Vascularization and innervation of blood vessels. The walls of large and medium arterial vessels are nourished both from the outside - through the vascular vessels (vasa vasorum), and from the inside - due to the blood flowing inside the vessel. Vascular vessels are branches of thin perivascular arteries running in the surrounding connective tissue. In the outer shell of the vessel wall, arterial branches branch, capillaries penetrate into the middle shell, the blood from which collects in the venous vessels of the vessels. The intima and inner zone of the middle tunic of the arteries do not have capillaries and are fed from the side of the lumen of the vessels. Due to the significantly lower strength of the pulse wave, the smaller thickness of the middle shell, and the absence of an internal elastic membrane, the mechanism of supply of the vein from the side of the cavity is not of particular importance. In the veins, the vasculature supplies arterial blood to all three membranes.

Constriction and dilation of blood vessels, maintaining vascular tone occur mainly under the influence of impulses coming from the vasomotor center. Impulses from the center are transmitted to the cells of the lateral horns of the spinal cord, from where they enter the vessels through sympathetic nerve fibers. The terminal branches of the sympathetic fibers, which contain the axons of the nerve cells of the sympathetic ganglia, form motor nerve endings on the cells of smooth muscle tissue. Efferent sympathetic innervation of the vascular wall determines the main vasoconstrictor effect. The question of the nature of vasodilators has not been completely resolved.

It has been established that parasympathetic nerve fibers are vasodilators in relation to the vessels of the head.

In all three membranes of the vessel walls, the terminal branches of the dendrites of nerve cells, mainly the spinal ganglia, form numerous sensory nerve endings. In the adventitia and perivascular loose connective tissue, among the free endings of various shapes, encapsulated bodies are also found. Specialized interoreceptors that perceive changes in blood pressure and its chemical composition, concentrated in the wall of the aortic arch and in the area where the carotid artery branches into internal and external - aortic and carotid reflexogenic zones, are of particular physiological importance. It has been established that in addition to these zones, there are a sufficient number of other vascular territories that are sensitive to changes in pressure and chemical composition of the blood (baro- and chemoreceptors). From the receptors of all specialized territories, impulses along the centripetal nerves reach the vasomotor center of the medulla oblongata, causing a corresponding compensatory neuroreflex reaction.

The structure and properties of the walls of blood vessels depend on the functions performed by the vessels in the entire human vascular system. As part of the walls of blood vessels, the inner ( intimacy), average ( media) and external ( adventitia) shells.

All blood vessels and cavities of the heart are lined from the inside with a layer of endothelial cells, which forms part of the vascular intima. The endothelium in intact vessels forms a smooth inner surface, which helps reduce resistance to blood flow, protects against damage and prevents thrombus formation. Endothelial cells participate in the transport of substances through vascular walls and respond to mechanical and other influences by the synthesis and secretion of vasoactive and other signaling molecules.

The inner lining (intima) of blood vessels also includes a network of elastic fibers, which is especially strongly developed in elastic-type vessels—the aorta and large arterial vessels.

IN middle layer Smooth muscle fibers (cells) are arranged in a circular pattern and can contract in response to various influences. There are especially many such fibers in muscular-type vessels - terminal small arteries and arterioles. When they contract, there is an increase in the tension of the vascular wall, a decrease in the lumen of blood vessels and blood flow in more distally located vessels until it stops.

Outer layer The vascular wall contains collagen fibers and fat cells. Collagen fibers increase the resistance of the walls of arterial vessels to high blood pressure and protect them and venous vessels from excessive stretching and rupture.

Rice. The structure of the walls of blood vessels

Table. Structural and functional organization of the vessel wall

Name	Characteristic
Endothelium (intima)	The inner, smooth surface of blood vessels, consisting primarily of a single layer of squamous cells, a basilar membrane and an internal elastic lamina
	Consists of several interpenetrating muscle layers between the inner and outer elastic plates
Elastic fibers	Located in the inner, middle and outer shells and form a relatively dense network (especially in the intima), they can easily be stretched several times and create elastic tension
Collagen fibers	Located in the middle and outer membranes, they form a network that provides much greater resistance to the stretching of the vessel than elastic fibers, but, having a folded structure, they counteract blood flow only if the vessel is stretched to a certain extent
Smooth muscle cells	They form the middle tunica, are connected to each other and to elastic and collagen fibers, creating active tension in the vascular wall (vascular tone)
Adventitia	It is the outer shell of the vessel and consists of loose connective tissue (collagen fibers) and fibroblasts. mast cells, nerve endings, and in large vessels additionally includes small blood and lymphatic capillaries, depending on the type of vessel it has different thickness, density and permeability

Functional classification and types of vessels

The activity of the heart and blood vessels ensures the continuous movement of blood in the body, its redistribution between organs depending on their functional state. A difference in blood pressure is created in the vessels; The pressure in large arteries is much higher than the pressure in small arteries. The pressure difference determines the movement of blood: blood flows from those vessels where the pressure is higher to those vessels where the pressure is low, from arteries to capillaries, veins, from veins to the heart.

Depending on the function performed, the vessels large and small are divided into several groups:

• shock-absorbing (elastic type vessels);
• resistive (vessels of resistance);
• sphincter vessels;
• exchange vessels;
• capacitive vessels;
• shunt vessels (arteriovenous anastomoses).

Shock absorbing vessels(main, vessels of the compression chamber) - aorta, pulmonary artery and all large arteries branching from them, arterial vessels of the elastic type. These vessels receive blood expelled by the ventricles under relatively high pressure (about 120 mm Hg for the left ventricle and up to 30 mm Hg for the right ventricle). The elasticity of the great vessels is created by a well-defined layer of elastic fibers located between the layers of endothelium and muscles. The shock-absorbing vessels stretch to accept the blood expelled under pressure by the ventricles. This softens the hydrodynamic impact of ejected blood on the walls of blood vessels, and their elastic fibers store potential energy, which is spent on maintaining blood pressure and moving blood to the periphery during diastole of the ventricles of the heart. Shock-absorbing vessels provide little resistance to blood flow.

Resistive vessels(resistance vessels) - small arteries, arterioles and metarterioles. These vessels offer the greatest resistance to blood flow, since they have a small diameter and contain a thick layer of circularly arranged smooth muscle cells in the wall. Smooth muscle cells, contracting under the influence of neurotransmitters, hormones and other vasoactive substances, can sharply reduce the lumen of blood vessels, increase resistance to blood flow and reduce blood flow in organs or their individual sections. When smooth muscle cells relax, vascular lumen and blood flow increase. Thus, resistive vessels perform the function of regulating organ blood flow and influencing the value of blood pressure.

Exchange vessels- capillaries, as well as pre- and post-capillary vessels through which water, gases and organic substances are exchanged between blood and tissues. The capillary wall consists of a single layer of endothelial cells and a basement membrane. There are no muscle cells in the capillary wall that could actively change their diameter and resistance to blood flow. Therefore, the number of open capillaries, their lumen, the speed of capillary blood flow and transcapillary exchange change passively and depend on the state of pericytes - smooth muscle cells located circularly around precapillary vessels, and the state of arterioles. When arterioles dilate and pericytes relax, capillary blood flow increases, and when arterioles constrict and pericytes contract, it slows down. A slowdown in blood flow in the capillaries is also observed when the venules narrow.

Capacitive vessels represented by veins. Due to their high distensibility, veins can accommodate large volumes of blood and thus provide a kind of deposition - slowing down the return to the atria. The veins of the spleen, liver, skin and lungs have especially pronounced depositing properties. The transverse lumen of the veins in conditions of low blood pressure has an oval shape. Therefore, with an increase in blood flow, the veins, without even stretching, but only taking on a more rounded shape, can accommodate more blood (deposit it). The walls of the veins have a pronounced muscle layer consisting of circularly arranged smooth muscle cells. As they contract, the diameter of the veins decreases, the amount of deposited blood decreases, and the return of blood to the heart increases. Thus, the veins are involved in regulating the volume of blood returning to the heart, influencing its contractions.

Shunt vessels- These are anastomoses between arterial and venous vessels. There is a muscle layer in the wall of the anastomosing vessels. When the smooth myocytes of this layer relax, the anastomosing vessel opens and its resistance to blood flow decreases. Arterial blood is discharged along a pressure gradient through the anastomosing vessel into the vein, and blood flow through the vessels of the microvasculature, including capillaries, decreases (even to the point of stopping). This may be accompanied by a decrease in local blood flow through the organ or part of it and disruption of tissue metabolism. There are especially many shunt vessels in the skin, where arteriovenous anastomoses are activated to reduce heat transfer when there is a threat of a decrease in body temperature.

Blood return vessels in the heart are represented by medium, large and hollow veins.

Table 1. Characteristics of the architectonics and hemodynamics of the vascular bed

Blood vessels are the most important part of the body, part of the circulatory system and penetrating almost the entire human body. They are absent only in the skin, hair, nails, cartilage and cornea of ​​the eyes. And if you collect them and stretch them into one even line, then the total length will be about 100 thousand km.

These tubular elastic formations continuously function, transferring blood from the constantly contracting heart to all corners human body, saturating them with oxygen and nourishing them, and then returning it back. By the way, the heart pushes more than 150 million liters of blood through the vessels throughout a human life.

There are the following main types of blood vessels: capillaries, arteries and veins. Each type performs its own specific functions. It is necessary to dwell on each of them in more detail.

Division into types and their characteristics

The classification of blood vessels varies. One of them involves division:

• on arteries and arterioles;
• precapillaries, capillaries, postcapillaries;
• veins and venules;
• arteriovenous anastomoses.

They represent a complex network, differing from each other in structure, size and their specific function, and form two closed systems connected to the heart - circulatory circles.

What is common in the device is the following: the walls of both arteries and veins have a three-layer structure:

• an inner layer that provides smoothness, built from endothelium;
• medium, which is a guarantee of strength, consisting of muscle fibers, elastin and collagen;
• the top layer of connective tissue.

The differences in the structure of their walls are only in the width of the middle layer and the predominance of either muscle fibers or elastic ones. And the fact is that venous ones contain valves.

Arteries

They deliver blood rich in nutrients and oxygen from the heart to all cells of the body. The structure of human arterial vessels is stronger than veins. This device (a denser and stronger middle layer) allows them to withstand the load of strong internal blood pressure.

The names of arteries, as well as veins, depend on:

Once upon a time it was believed that arteries carried air and therefore the name is translated from Latin as “containing air.”

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The following types are distinguished:

The arteries, leaving the heart, thin out into small arterioles. This is the name given to the thin branches of the arteries that pass into the precapillaries, which form capillaries.

These are the finest vessels, with a diameter much thinner than a human hair. This is the longest part of the circulatory system, and their total quantity in the human body ranges from 100 to 160 billion.

The density of their accumulation varies everywhere, but is greatest in the brain and myocardium. They consist only of endothelial cells. They carry out a very important activity: chemical exchange between the bloodstream and tissues.

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The capillaries subsequently connect with postcapillaries, which become venules - small and thin venous vessels that flow into the veins.

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These are blood vessels through which oxygen-depleted blood is flowing back to the heart.

The walls of veins are thinner than the walls of arteries because there is no strong pressure. The most developed layer smooth muscles in the middle wall of the vessels of the legs, because moving up is not easy work for the blood under the influence of gravity.

The venous vessels (all except the superior and inferior vena cava, pulmonary, nuchal, renal, and cephalic veins) contain special valves that allow blood to move toward the heart. The valves block its reverse outflow. Without them, the blood would flow to the feet.

Arteriovenous anastomoses are branches of arteries and veins connected to each other by anastomoses.

Division by functional load

There is another classification that blood vessels undergo. It is based on the difference in the functions they perform.

There are six groups:

There is another very interesting fact regarding this unique system of the human body. If you are overweight, more than 10 km (per 1 kg of fat) of additional blood-carrying vessels are created in the body. All this creates a very large load on the heart muscle.

Heart disease and excess weight, and even worse, obesity, are always very closely related. But the good thing is that the human body is also capable of the reverse process - removing unnecessary blood vessels when getting rid of excess fat (namely, from it, and not just from extra pounds).

What role do blood vessels play in human life? Overall, they do very serious and important work. They are transport that ensures the delivery of necessary substances and oxygen to every cell of the human body. They also remove carbon dioxide and waste from organs and tissues. Their importance cannot be overestimated.

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BLOOD VESSELS (vasa sanguifera s. sanguinea) - elastic tubes of various calibers that make up a closed system through which blood flows in the body from the heart to the periphery and from the periphery to the heart. The cardiovascular system of animals and humans ensures the transport of substances in the body and thereby participates in metabolic processes. It contains a circulatory system with central authority- the heart (see), which acts as a pump, and the lymphatic system (see).

Comparative anatomy

The vascular system arises in the body of multicellular animals due to the need for cell life support. Nutrients absorbed from the intestinal tube are transported by fluid flow throughout the body. Extravascular transport of fluids through intertissue spaces is replaced by intravascular circulation; in humans, approx. 20% of the total body fluid. Many invertebrate animals (insects, mollusks) have an open vascular system (Fig. 1, a). In annelids, a closed circulation of hemolymph appears (Fig. 1, b), although they do not yet have a heart, and the pushing of blood through the vessels occurs due to the pulsation of 5 pairs of “heart”-pulsating tubes; contractions of the body muscles help these “hearts”. In lower vertebrates (lancelet) the heart is also absent, the blood is still colorless, the differentiation of arteries and veins is well expressed. In fish, at the anterior end of the body, near the gill apparatus, an expansion of the main vein appears, where the veins of the body are collected - venous sinus(Fig. 2), behind it are the atrium, ventricle and conus arteriosus. From it, blood enters the ventral aorta with its arterial branchial arches. At the border of the venous sinus and the conus arteriosus, a valve appears that regulates the passage of blood. The fish heart allows only venous blood to pass through. Gases are exchanged in the capillaries of the gill filaments, and oxygen dissolved in water enters the blood to further follow through the dorsal aorta into the circulation and spread into the tissues. As a result of the change from gill breathing to pulmonary breathing in terrestrial animals (amphibians), a small (pulmonary) circulation appears, and with it a three-chambered heart appears, consisting of two atria and one ventricle. The appearance of an incomplete septum in it is characteristic of reptiles, and crocodiles already have a four-chambered heart. Birds and mammals, like humans, also have a four-chambered heart.

The appearance of the heart is due to an increase in tissue mass and an increase in resistance to blood flow. The original vessels (protocapillaries) were indifferent, equally loaded, and homogeneous in structure. Then the vessels delivering blood to a segment of the body or to an organ acquired structural features characteristic of arterioles and arteries; the vessels at the exit of blood from the organ became veins. Between the primitive arterial vessels and the blood outflow pathways, a capillary network of the organ was formed, which took over all metabolic functions. Arteries and veins have become typically transport vessels, some primarily resistive (arteries), others primarily capacitive (veins).

The arterial system in the process of evolutionary development turned out to be connected with the main arterial trunk - the dorsal aorta. Its branches penetrated all segments of the body, stretched along the hind limbs, and took over the blood supply to all organs abdominal cavity and pelvis. From the ventral aorta with its branchial arches came the carotid arteries (from the third pair of branchial arterial arches), the aortic arch and the right subclavian artery (from the fourth pair of branchial arterial arches), the pulmonary trunk with the ductus arteriosus and pulmonary arteries (from the sixth pair of arterial branchial arches). As it becomes arterial system In primates and humans, a restructuring of arterial links occurred. Thus, the caudal artery has disappeared; the remnant of the cut in humans is the median sacral artery. Instead of several renal arteries, a paired renal artery was formed. The arteries of the limbs underwent complex transformations. For example, from the interosseous artery of the extremity of reptiles in mammals, the axillary, brachial, and median emerged, which later became the ancestor of the radial and ulnar arteries. The sciatic artery, the main arterial route of the hind limb of amphibians and reptiles, gave way to the femoral artery.

In the history of the development of venous vessels, the existence of two portal systems in lower vertebrates is noted - hepatic and renal. The renal portal system is well developed in fish, amphibians, and reptiles, but weakly in birds.

With the reduction of the primary kidney in reptiles, the portal renal system disappeared. The final kidney appeared with its glomeruli and blood flow into the inferior vena cava. The paired anterior cardinal veins, which receive blood from the head in fish, as well as the paired posterior cardinal veins, lost their importance with the transition of animals to terrestrial life. Amphibians also retain the collectors that connect them - the ducts of Cuvier, which flow into the heart, but over time, in higher vertebrates, only the coronary sinus of the heart remains of them. Of the paired symmetrical anterior cardinal veins in humans, the internal jugular veins are preserved, merging together with the subclavian veins into the superior vena cava; of the posterior cardinal veins, the asymmetrical azygos and semi-amygos veins are preserved.

The portal system of the liver occurs in fish in connection with the intestinal vein. Initially, the hepatic veins flowed into the venous sinus of the heart, where blood flowed from the cardinal veins through the right and left ducts of Cuvier. With the extension of the venous sinus of the heart in the caudal direction, the mouths of the hepatic veins moved caudally. The trunk of the inferior vena cava has formed.

The lymphatic system developed as a derivative of the venous system or independently of it due to the parallel flow of interstitial fluids as a result of the fusion of mesenchymal spaces. It is also assumed that the predecessor of the circulatory and lymphatic channels in vertebrates was the hemolymphatic system of invertebrates, through which nutrients and oxygen were transferred to the cells.

Anatomy

The blood supply to all organs and tissues in the human body is carried out by vessels of the systemic circulation. It starts from the left ventricle of the heart with the largest arterial trunk - the aorta (see) and ends in the right atrium, into which the largest venous vessels of the body flow - the superior and inferior vena cava (see). Along the aorta from the heart to the V lumbar vertebra, numerous branches depart from it - to the head (color fig. 3) the common carotid arteries (see Carotid artery), to the upper extremities - the subclavian arteries (see Subclavian artery), to the lower extremities - iliac arteries. Arterial blood is delivered through the thinnest branches to all organs, including skin, muscles, and skeleton. There, passing through the microcirculatory bed, the blood gives off oxygen and nutrients, captures carbon dioxide and waste products to be removed from the body. Through postcapillary venules, blood that has become venous enters the tributaries of the vena cava.

Called the “pulmonary circulation”, there is a complex of vessels that passes blood through the lungs. Its beginning is the pulmonary trunk emerging from the right ventricle of the heart (see), along which venous blood flows into the right and left pulmonary arteries and further into the capillaries of the lungs (printing Fig. 4). Here the blood gives off carbon dioxide, and picks up oxygen from the air and is sent from the lungs through the pulmonary veins to the left atrium.

From the blood capillaries of the digestive tract, blood collects in the portal vein (see) and goes to the liver. There it spreads through the labyrinths of thin vessels - sinusoidal capillaries, from which tributaries of the hepatic veins are then formed, flowing into the inferior vena cava.

Larger K. s. of the main ones follow between organs and are designated as arterial mains and venous collectors. Arteries lie, as a rule, under the cover of muscles. They are sent to the blood supply organs along the shortest route. In accordance with this, they are located on the flexor surfaces of the limbs. The correspondence of the arterial highways to the main skeletal formations is observed. There is a differentiation of visceral and parietal arteries, the latter in the trunk region retain a segmental character (for example, intercostal arteries).

The distribution of arterial branches in organs, according to M. G. Gain, is subject to certain laws. In parenchymal organs, there is either a gate through which an artery enters the interior, sending branches in all directions, or the arterial branches successively stepwise enter the organ along its length and are connected inside the organ by longitudinal anastomoses (for example, muscle), or, finally, penetrate the organ arterial branches from several sources along radii (e.g. thyroid gland). Arterial blood supply to hollow organs occurs in three types - radial, circular and longitudinal.

All veins in the human body are localized either superficially, in subcutaneous tissue, or in the depths of anatomical regions along the course of arteries, usually accompanied by pairs of veins. Superficial veins, thanks to multiple anastomoses, form venous plexuses. Deep venous plexuses are also known, for example, the pterygoid on the head, the epidural in the spinal canal, around the pelvic organs. A special type of venous vessels are the sinuses of the dura mater of the brain.

Variations and abnormalities of large blood vessels

K. s. They vary quite widely in their position and size. There are malformations of blood cells that lead to pathology, as well as deviations that do not affect human health. The first include coarctation of the aorta (see), patent ductus arteriosus (see), departure of one of the coronary arteries heart from the pulmonary trunk, phlebectasis of the internal jugular vein, arteriovenous aneurysms (see Aneurysm). Much more often in practically healthy people there are varieties of the normal location of blood vessels, cases of their unusual development, compensated by reserve vessels. Thus, with dextrocardia, a right-sided position of the aorta is noted. Duplication of the superior and inferior vena cava does not cause any patol, disorders. There are very diverse options for the origin of branches from the aortic arch. Sometimes accessory arteries (eg, hepatic) and veins are identified. Often there is either a high fusion of veins (for example, the common iliac when forming the inferior vena cava), or, conversely, a low one. This is reflected in the total length of the K. s.

It is advisable to divide all variations of K. s. depending on their location and topography, on their number, branching or merging. When blood flow through natural highways is disrupted (for example, due to injury or compression), new blood flow paths are formed, creating an atypical picture of the distribution of blood cells. (acquired anomalies).

Research methods

Anatomical research methods. There are different methods for studying K. s. on dead preparations (dissection, injection, impregnation, staining, electron microscopy) and methods of intravital experimental research (x-ray, capillaroscopy, etc.). Filling out the K. s. Anatomists began to use dye solutions or solidifying masses back in the 17th century. Great successes in injection technology were achieved by anatomists J. Swammerdam, F. Ruysch and I. Lieberkühn.

On anatomical preparations, arterial injection is achieved by inserting an injection needle into the lumen of the vessel and filling it with a syringe. It is more difficult to inject veins that have valves inside them. In the 40s 20th century A. T. Akilova, G. M. Shulyak proposed a method of injecting veins through the spongy substance of bones, where an injection needle is inserted.

In the manufacture of vascular preparations, the injection method is often combined with the corrosion method, developed in the mid-19th century by J. Hirtl. The mass introduced into the vessels (molten metals, hot solidifying substances - wax, paraffin, etc.) produces impressions choroid plexuses, the composition of which remains strong after melting of all surrounding tissues (Fig. 3). Modern plastic materials create conditions for obtaining corrosive preparations of jewelry fineness.

Of particular value is the injection of K. s. solution of silver nitrate, which allows you to see the boundaries of endothelial cells when studying their walls. Impregnation K. s. silver nitrate by immersing fragments of organs or membranes in a special solution was developed by V.V. Kupriyanov in the 60s. 20th century (color fig. 2). She laid the foundation for non-injection methods for studying the vascular bed. These include fluorescent microscopy of microvessels, histochemistry, their identification, and subsequently electron microscopy (including transmission, scanning, raster) of vascular walls. In the experiment, intravital injection of radiopaque suspensions into vessels (angiography) is widely carried out for the purpose of diagnosing developmental anomalies. An auxiliary method should be considered radiography of blood vessels, into the lumen of which a catheter made of radiopaque materials is inserted.

Thanks to the improvement of optics for capillaroscopy (see), it is possible to observe K. s. and capillaries in the conjunctiva of the eyeball. Reliable results are obtained by photographing K. s. retina through the pupil using a retinophot apparatus.

Data from an intravital study of the anatomy of K. s. in experimental animals are documented by photographs and films, on which precise morphometric measurements are made.

Research methods in the clinic

Examination of a patient with various pathologies K.s., like other patients, should be comprehensive. It begins with anamnesis, examination, palpation and auscultation and ends with instrumental methods of examination, bloodless and surgical.

Bloodless study of K. s. should be carried out in an isolated, spacious, well-lit (preferably daylight) room with a constant temperature of at least 20°. Surgical research methods must be carried out in a specially equipped X-ray operating room, equipped with everything necessary, including to combat possible complications, in full compliance with asepsis.

When collecting anamnesis, pay special attention to occupational and household hazards (frostbite and frequent cooling of the extremities, smoking). Among the complaints, special attention should be paid to chilliness of the lower extremities, rapid fatigue when walking, paresthesia, dizziness, unsteadiness of gait, etc. Particular attention is paid to the presence and nature of pain, a feeling of heaviness, fullness, rapid fatigue of the limb after standing or physical exercise. stress, swelling, skin itching. They establish the dependence of complaints on the position of the body, the time of year, find out their connection with general diseases, injury, pregnancy, operations, etc. Be sure to clarify the sequence and time of occurrence of each complaint.

The patient is undressed and examined in a supine and standing position, while comparing symmetrical areas of the body and especially the limbs, noting their configuration, skin color, the presence of areas of pigmentation and hyperemia, the nature of the pattern of the saphenous veins, the presence of dilation of the superficial veins and their nature, localization and prevalence . While examining the lower extremities, pay attention to the vascular pattern of the anterior abdominal wall, gluteal regions and lower back. When examining the upper extremities, the condition of the vessels and skin of the neck is taken into account, shoulder girdle and chest. At the same time, attention is paid to the difference in the circumference and volume of individual segments of the limbs in a horizontal and vertical position, the presence of edema and pulsating formations along the vascular bundles, the severity of the hairline, the color and dryness of the skin, and in particular its individual areas.

The skin turgor, the severity of the skin fold, seals along the vessels, painful points, the localization and size of defects in the aponeurosis are determined, the skin temperature of different parts of the same limb and in symmetrical areas of both limbs is compared, the skin in the area of ​​trophic lesions is palpated.

When examining the state of blood circulation in the extremities, palpation of the main arteries is of some value. Palpation of the pulse in each individual case should be done in all points of the vessels accessible for palpation bilaterally. Only under this condition can a difference in the size and character of the pulse be detected. It should be noted that with swelling of the tissues or significantly pronounced subcutaneous fat, determining the pulse is difficult. The absence of pulsation in the arteries of the foot cannot always be considered a reliable sign of circulatory disorders of the limb, since this is observed in anatomical variants of the localization of blood vessels.

The diagnosis of vascular diseases is greatly enriched by listening to C. and recording of phonograms. This method allows us to detect not only the presence of stenosis or aneurysmal dilatation of the arterial vessel, but also their location. Using phonangiography, you can determine the intensity of noise and its duration. New ultrasound equipment based on the Doppler phenomenon will also help in diagnosis.

For thrombolytic diseases K. s. extremities, it is very important to identify peripheral circulatory insufficiency. For this purpose, various functions and tests are proposed. The most common of them are the Oppel test, the Samuels test and the Goldflam test.

Oppel test: the patient in a supine position is asked to raise the lower limbs to an angle of 45° and hold them in this position for 1 minute; with insufficiency of peripheral circulation, blanching appears in the area of ​​the sole, which is normally absent.

Samuels test: the patient is asked to raise both extended lower limbs to an angle of 45° and perform 20-30 flexion-extension movements in ankle joints; blanching of the soles and the time of its onset indicate the presence and severity of circulatory disorders in the limb.

The Goldflam test is performed using the same method as the Samuels test: the time of onset of muscle fatigue on the affected side is determined.

To clarify the condition of the valve apparatus of the veins, functional tests are also carried out. Insufficiency of the ostial (inlet) valve of the great saphenous vein of the leg is established using the Troyanov-Trendelenburg test. The patient in a horizontal position raises the lower limb until the saphenous veins are completely emptied. A rubber tourniquet is applied to the upper third of the thigh, after which the patient stands up. The tourniquet is removed. With valvular insufficiency, dilated veins fill retrogradely. For the same purpose, a Hackenbruch test is performed: in an upright position, the patient is asked to cough vigorously, while a push of blood is felt with the hand lying on the dilated vein of the thigh.

The patency of the deep veins of the lower extremities is determined by the Delbe-Perthes test. In an upright position, a rubber tourniquet is applied to the patient in the upper third of the leg and asked to walk. If the superficial veins empty at the end of the walk, then deep veins passable. For the same purpose, a lobeline test can be used. After elastic bandaging of the entire lower limb, 0.3-0.5 ml of 1% lobeline solution is injected into the veins of the dorsum of the foot. If within 45 sec. If a cough does not appear, the patient is asked to walk in place. If there is no cough, continue for another 45 seconds. It is believed that the deep veins are impassable.

The state of the valve apparatus of the perforating veins of the leg can be judged by the results of the Pratt, Sheinis, Talman and five-bundle tests.

Pratt's test: in a horizontal position, the patient's raised leg is bandaged with an elastic bandage, starting from the foot to the upper third of the thigh; a tourniquet is applied above; the patient gets up; Without loosening the tourniquet, remove the previously applied bandage, turn by turn, and begin to apply another bandage from top to bottom, leaving gaps of 5-7 cm between the first and second bandages; the appearance of vein protrusions in these spaces indicates the presence of incompetent perforating veins.

Sheinis test: after applying three tourniquets to an elevated leg, the patient is asked to walk; By filling the veins between the tourniquets, the localization of insufficient perforating veins is determined.

Thalmann test: one long rubber tourniquet is applied in the form of a spiral on an elevated leg with emptied veins and the patient is asked to walk; the decoding of the results is the same as with the Sheinis test.

Five-bundle test: carried out in the same way, but with the application of two tourniquets on the thigh and three on the lower leg.

The indicated wedges and samples are only qualitative. They cannot be used to determine the amount of retrograde blood flow. To some extent, Alekseev’s method allows us to establish it. The limb being examined is raised upward until the saphenous veins are completely emptied. A Beer bandage is applied to the upper third of the thigh, compressing both veins and arteries. The limb being examined is lowered into a special vessel filled to the brim with warm water. There is an outlet pipe at the top edge of the vessel to drain the displaced water. Once the limb is immersed, the amount of water displaced is accurately measured. Then remove the bandage and after 15 seconds. The amount of additionally displaced water is measured, which is designated as the total volume of arteriovenous inflow (V1). Then everything is repeated again, but with a cuff below the Beer bandage, maintaining a constant pressure of 70 mm Hg. Art. (for compression of veins only). The amount of displaced water is designated as the volume of arterial inflow in 15 seconds. (V2). The volumetric velocity (S) of retrograde venous filling (V) is calculated by the formula:

S = (V1 - V2)/15 ml/sec.

From the extensive arsenal of instrumental methods used to examine patients with diseases of peripheral arteries, especially widely in angiolas. in practice, arterial oscillography is used (see), reflecting pulse fluctuations of the arterial wall under the influence of changing pressure in the pneumatic cuff. This technique allows you to determine the main parameters of blood pressure (maximum, average, minimum), identify changes in pulse (tachycardia, bradycardia) and heart rhythm disturbances (extrasystole, atrial fibrillation). Oscillography is widely used to determine the reactivity, elasticity of the vascular wall, its ability to expand, and to study vascular reactions (Fig. 4). The main indicator in oscillography is the gradient of the oscillographic index, which, if present, vascular pathology indicates the level and severity of the lesion.

From the oscillograms obtained during the study of the limbs at various levels, it is possible to determine the place where a relatively high oscillatory index is observed, that is, practically the place of narrowing of the vessel or thrombus. Below this level, the oscillatory index decreases sharply, since the movement of blood below the thrombus occurs along collaterals, and pulse fluctuations become smaller or completely disappear and are not displayed on the curve. Therefore, for a more detailed study, it is recommended to record oscillograms at 6-8 different levels of both limbs.

With obliterating endarteritis, there is a decrease in the amplitude of oscillations and the oscillatory index, primarily in the dorsal arteries of the feet. As the process progresses, a decrease in the index is also noted on the lower leg (Fig. 4, b). At the same time, deformation of the oscillographic curve occurs, the edges in this case become stretched, the elements of the pulse wave in it turn out to be poorly expressed, and the top of the teeth acquires a vaulted character. The oscillatory index on the thigh, as a rule, remains within normal limits. In case of obstruction of the bifurcation of the aorta and arteries in the iliofemoral zones, oscillography does not make it possible to determine the upper level of blockage of the vessel.

With obliterating atherosclerosis in the area of ​​the iliac or femoral zone patol, changes in the oscillogram occur mainly when measured in the proximal limbs (Fig. 4, c). A feature of proximal forms of damage to the arteries of the extremities is often the presence of two blocks, which can occur on one or both limbs of the same name only at different levels. Oscillography is more indicative of obstruction in the underlying segments (thigh, lower leg). It establishes the upper level of the lesion, but does not make it possible to judge the degree of compensation of collateral circulation.

One of the methods of angiography is aortography (see). There are direct and indirect aortography. Among the methods of direct aortography, only translumbar aortography has retained its significance - a method in which the aorta is punctured using a translumbar approach and the contrast agent is injected directly through the needle (Fig. 14). Direct aortography methods such as puncture of the ascending aorta, its arch and the descending thoracic aorta, in modern clinics do not apply.

Indirect aortography consists of introducing contrast agent into the right side of the heart or into the pulmonary artery through a catheter and receiving the so-called. levograms. In this case, the catheter is passed into the right atrium, right ventricle or pulmonary artery trunk, where a contrast agent is injected. After passing through the vessels of the pulmonary circle, the aorta is contrasted, and the edges are recorded on a series of angiograms. The use of this method is limited due to the strong dilution of the contrast agent in the vessels of the pulmonary circulation and, therefore, “tight” contrasting of the aorta is not enough. However, in cases where it is impossible to perform retrograde catheterization of the aorta through the femoral or axillary arteries, it may be necessary to use this method.

Ventriculoaortography is a method of introducing a contrast agent into the cavity of the left ventricle of the heart, from where it flows through the natural blood flow into the aorta and its branches. The injection of a contrast agent is carried out either through a needle, the edges are injected percutaneously directly into the cavity of the left ventricle, or through a catheter drawn from the right atrium by transseptal puncture of the interatrial septum into the left atrium and then into the left ventricle. The second method is less traumatic. These methods of contrasting the aorta are used extremely rarely.

The counter-flow method consists of percutaneous puncture of the axillary or femoral artery, passing the needle along the conductor retrograde to the blood flow into the vessel in order to better fix it and injecting a significant amount of contrast agent under high pressure against the blood flow. For better contrast in order to reduce cardiac output, an injection of a contrast agent is combined with the patient performing a Valsalva maneuver. The disadvantage of this method is severe overstretching of the vessel, which can lead to damage to the inner lining and subsequent thrombosis.

Percutaneous catheterization aortography is used most often. The femoral artery is usually used to pass the catheter. However, it can also be used axillary artery. Through these vessels, catheters of sufficiently large caliber can be inserted and, therefore, a contrast agent can be injected under high pressure. This makes it possible to more clearly contrast the aorta and adjacent branches.

To study the arteries, arteriography is used (see), the edges are performed by direct puncture of the corresponding artery and retrograde injection of a contrast agent into its lumen or by percutaneous catheterization and selective angiography. Direct puncture of the artery and angiography are performed mainly with contrasting of the arteries of the lower extremities (Fig. 15), less often - the arteries of the upper extremities, common carotid, subclavian and vertebral arteries.

Catheterization arteriography is performed for arteriovenous anastomoses of the lower extremities. In these cases, the catheter is passed antegrade on the affected side or retrograde through the contralateral femoral and iliac arteries to the aortic bifurcation and then antegrade along the iliac arteries on the affected side and further in the distal direction to the required level.

For contrasting the brachiocephalic trunk, arteries of the shoulder girdle and upper extremities, as well as the arteries of the thoracic and abdominal aorta, transfemoral retrograde catheterization is more indicated. Selective catheterization requires the use of catheters with a specially modeled beak or the use of controlled systems.

Selective arteriography provides the most complete picture of the angioarchitecture of the area under study.

When studying the venous system, puncture catheterization of veins is used (see. Catheterization of veins, puncture). It is carried out using the Seldinger method by percutaneous puncture of the femoral, subclavian and jugular veins and passing the catheter through the blood flow. These approaches are used for catheterization of the superior and inferior vena cava, hepatic and renal veins.

Vein catheterization is carried out in the same way as arterial catheterization. Due to the lower blood flow rate, the contrast agent injection is performed under lower pressure.

Contrasting the system of the superior and inferior vena cava (see Cavography), renal, adrenal and hepatic veins is also carried out by catheterization.

Phlebography of the extremities is performed by introducing a contrast agent through the bloodstream through a puncture needle or through a catheter inserted into one of the peripheral veins by venosection. There is distal (ascending) venography, retrograde femoral venography, pelvic venography, retrograde venography of the leg veins, retrograde iliocavography. All studies are carried out by introducing X-ray contrast agents intravenously (see Phlebography).

Usually, to contrast the veins of the lower extremities, the dorsal vein of the big toe or one of the dorsal metatarsal veins is punctured or exposed, and a catheter is inserted into it. To prevent the contrast agent from entering the superficial veins of the lower leg, the legs are bandaged. The patient is placed in a vertical position and a contrast agent is injected. If you inject a contrast agent against the background of the Valsalva maneuver, then with moderate valvular insufficiency, reflux of the contrast agent into the femoral vein may occur, and with severe valvular insufficiency, reflux of the contrast agent can reach the veins of the leg. The X-ray image of the veins is recorded using a series of radiographs and the X-ray cinematography method.

Many changes in K. s. are in essence compensatory-adaptive. These, in particular, include atrophy of arteries and veins, manifested by a decrease in the number of contractile elements in their walls (mainly in the middle shell). Such atrophy can develop both physiologically (involution ductus arteriosus, umbilical vessels, ductus venosus in the postembryonic period), and on a pathological basis (emptiness of arteries and veins when they are compressed by a tumor, after ligation) basis. Often, adaptive processes are manifested by hypertrophy and hyperplasia of smooth muscle cells and elastic fibers of the walls of the blood cell. An illustration of such changes can be elastosis and myoelastosis of arterioles and small arterial vessels of the systemic circulation during hypertension and a largely similar restructuring of the structure of the arteries of the lungs with hypervolemia of the pulmonary circulation, which occurs with some congenital heart defects. The strengthening of collateral circulation, accompanied by recalibration and new formation of blood cells, is of exceptionally great importance in restoring hemodynamic disorders in organs and tissues. in the patol zone, obstructions to blood flow. Adaptive manifestations also include “arterialization” of veins, for example, in arteriovenous aneurysms, when at the site of anastomosis the veins acquire histol, a structure approaching the structure of arteries. The adaptive essence is also carried by changes in the arteries and veins after the creation of artificial vascular anastomoses (arterial, venous, arteriovenous) with treatment. purpose (see Bypass of blood vessels). In the hemomicrocirculation system, adaptive processes are morphologically characterized by the formation and restructuring of terminal vessels (precapillaries into arterioles, capillaries and postcapillaries into venules), increased blood discharge from the arteriolar to venular with an increase in the number of arteriovenular shunts, hypertrophy and hyperplasia of smooth muscle cells in the precapillary sphincters, the closure of which is prevented the entry of excessive amounts of blood into the capillary networks, an increase in the degree of tortuosity of arterioles and precapillaries with the formation of loops, curls and glomerular structures along their course (Fig. 19), which contribute to the weakening of the force of the pulse impulse in the arteriolar part of the microcirculatory bed.

Extremely diverse morphol. changes occur during autotransplantation, allotransplantation and xenotransplantation of K. s. using autologous, allogeneic and xenogeneic vascular grafts, respectively. Thus, in venous autografts transplanted into arterial defects, the processes of organizing graft structures that are losing their viability with their replacement by connective tissue and the phenomenon of reparative regeneration with the new formation of elastic fibers and smooth muscle cells develop, culminating in the “arterialization” of the autovein. In the case of replacement of a defect in an arterial vessel with a lyophilized allogeneic artery, a “sluggish” rejection reaction occurs, accompanied by gradual destruction of the graft, the organization of dead tissue substrate and restoration processes leading to the formation of a new vessel, characterized by the predominance of collagen fibrils in its walls. With plastic surgery K. s. with the help of synthetic prostheses (explantation), the walls of the latter are covered with a fibrinous film, grow with granulation tissue and undergo encapsulation with subsequent endothelialization of their inner surface (Fig. 20).

Changes in K. s. with age they reflect the processes of their physiol, postembryonic growth, adaptation to changing hemodynamic conditions and senile involution during life. Senile changes in blood vessels in general are manifested by atrophy in the walls of arteries and veins of contractile elements and reactive proliferation of connective tissue, Ch. arr. in the inner shell. In the arteries of elderly people, involutive sclerotic processes are combined with atherosclerotic changes.

Pathology

Malformations of blood vessels

Malformations of blood vessels, or angiodysplasia, - congenital diseases, manifested by anatomical and functional disorders of the vascular system. In the literature these defects are described under different names: branched angioma (see Hemangioma), phlebectasia (see Angiectasia), angiomatosis (see), phlebarteriectasia, Parkes Weber syndrome (see Parkes Weber syndrome), Klippel-Trenaunay syndrome, arteriovenous angioma, etc.

Malformations of K. s. occur in 7% of cases of patients with other congenital vascular diseases. The vessels of the extremities, neck, face, and scalp are most often affected.

Based on the anatomical and morphol. signs of malformations of K. s. can be divided into the following groups: 1) malformations of veins (superficial, deep); 2) malformations of arteries; 3) arteriovenous defects (arteriovenous fistulas, arteriovenous aneurysms, arteriovenous vascular plexuses).

Each of the above types of angiodysplasia can be single or multiple, limited or widespread, and combined with other developmental defects.

The etiology has not been fully elucidated. It is believed that for the formation of the defect K. s. a number of factors matter: hormonal, temperature

tour, fetal injury, inflammation, infection, toxicosis. According to Malan and Puglionisi (E. Malan, A. Puglionisi), the occurrence of angio-dysplasia is the result of a complex violation of the embryogenesis of the vascular system.

Malformations of the superficial veins are the most common and account for 40.8% of all angiodysplasias. The process involves either only the saphenous veins, or it spreads to deeper tissues and affects the veins of the muscles, intermuscular spaces, and fascia. There is a shortening of the bones and an increase in the volume of soft tissues. Localization of the defect is the upper and lower extremities.

Morphologically, the defect is manifested by a number of structural features that are pathognomonic for this species. Some of them include angiomatous complexes with smooth muscle fibers in the walls of blood vessels; others are represented by ectatic, thin-walled veins with uneven lumen; still others are sharply dilated veins of the muscular type, in the walls of which a chaotic orientation of smooth muscles is found.

Rice. 22. Lower limbs of a 2.5-year-old child with a malformation of the deep veins of the extremities (Klippel-Trenaunay syndrome): the limbs are enlarged, swollen, there are extensive vascular spots on the skin, the saphenous veins are dilated.

Rice. 23. The lower part of the face and neck of a 6-year-old child with phlebectasis of the internal jugular veins: on the anterior surface of the neck there are spindle-shaped formations, more on the left (the picture was taken when the patient was tense).

Rice. 24. Lower limbs of a 7-year-old child with right-sided congenital arteriovenous defects: the right limb is enlarged in size, the saphenous veins are dilated, there are pigment spots in certain areas of the limb (the limb is in a forced position due to contracture).

Clinically, the defect manifests itself as varicose veins of the saphenous veins. The expansion of veins can be different - stem, nodal, in the form of conglomerates. Combinations of these forms are often found. The skin over the dilated veins is thinned and bluish in color. The affected limb is enlarged in volume and deformed, which is associated with blood overflow in the dilated venous vessels (Fig. 21). Characteristic signs are symptoms of emptying and sponges, the essence of which is a decrease in the volume of the affected limb at the time of its lifting up or when pressing on the dilated venous plexuses as a result of the emptying of vicious vessels.

On palpation, tissue turgor is sharply reduced, movements in the joints are often limited due to bone deformation and dislocations. Constant severe pain and trophic disorders are observed.

Phlebograms show dilated, deformed veins, accumulation of contrast material in the form of shapeless spots.

Treatment consists of removing the affected tissues and vessels as completely as possible. In especially severe cases, when radical treatment is impossible, the patol formations are partially excised and multiple suturings of the remaining altered areas are performed with silk or nylon sutures. For widespread lesions, surgical treatment should be carried out in several stages.

Malformations of the deep veins are manifested by a congenital disorder of blood flow through the main veins. Occurs in 25.8% of cases of all angiodysplasias. Damage to the deep veins of the extremities is described in the literature as Klippel-Trenaunay syndrome, which for the first time in 1900 characterized the wedge, the picture of this defect.

Morphol, the study of the defect allows us to distinguish two variants of the anatomical “block”: dysplastic process main vein and its external compression, caused by disorganization of arterial trunks, muscles, as well as fibrous cords and tumors. The histoarchitecture of the saphenous veins indicates the secondary, compensatory nature of ectasia.

Klippel-Trenaunay syndrome is observed only in the lower extremities and is characterized by a triad of symptoms: varicose veins of the saphenous veins, an increase in the volume and length of the affected limb, pigmented or vascular spots (Fig. 22). Patients complain of heaviness in the limbs, pain, and fatigue. Constant signs are hyperhidrosis, hyperkeratosis, and ulcerative processes. TO associated symptoms should include bleeding from the intestines and urinary tract, deformation of the spine and pelvis, and joint contractures.

In the diagnosis of the defect, the leading role belongs to phlebography, which reveals the level of the block of the main vein, its length, the condition of the saphenous veins, for which the identification of embryonic trunks by outer surface limbs and along the sciatic nerve is considered a characteristic sign of the defect.

Treatment is fraught with certain difficulties. Radical treatment with normalization of blood flow is possible with external compression of the vein and consists of eliminating the blocking factor. In cases of aplasia or hypoplasia, restoration of blood flow by plastic surgery of the main vein is indicated, however, such operations are associated with the risk of graft thrombosis. It should be especially emphasized that attempts to remove dilated saphenous veins when blood flow through the main veins has not been restored is fraught with the risk of severe venous insufficiency in the limb and its death.

Congenital phlebectasias of the jugular veins account for 21.6% of other vascular defects.

Morphol, the picture is characterized by pronounced underdevelopment of the muscular-elastic framework of the vein wall, up to its complete absence.

Clinically, the defect is manifested by the appearance of a tumor-like formation on the patient’s neck during a cry (Fig. 23), which in the normal state disappears and is not detected. With phlebectasias of the internal jugular veins, the formation has a fusiform shape and is located in front of the sternocleidomastoid muscle. Phlebectasias of the saphenous veins of the neck have a round or stem shape and are well contoured under the skin. With phlebectasias of the internal jugular veins associated symptoms There may be hoarseness and difficulty breathing. Complications of the defect include wall ruptures, thrombosis and thromboembolism.

Treatment of patients is only surgical. For phlebectasias of the saphenous veins, excision of the affected areas of the vessels is indicated. For phlebectasias of the internal jugular veins, the method of choice is to strengthen the vein wall with an implant.

Defects of arterial peripheral vessels are observed extremely rarely and are expressed in the form of narrowing or aneurysm-like dilation of the arteries. The wedge, the picture of these defects and surgical tactics do not differ from those for acquired lesions of the arteries.

Arteriovenous defects are manifested by congenital arteriovenous communications in the form of fistulas, aneurysms, and choroid plexuses. Compared to other angiodysplasias, arteriovenous malformations are observed less frequently and occur in 11.6% of cases. They can be observed in all organs, but the limbs are most often affected and are local or widespread.

Typical morphol. change on the part of K. s. is their restructuring in the form of “arterialization” of veins and “venization” of arteries.

Wedge, the picture of congenital arteriovenous defects consists of local and general symptoms.

Local symptoms include: hypertrophy of the affected organ, “osteomegaly”, varicose dilation and pulsation of the saphenous veins, pigment or vascular spots (Fig. 24), increased pulsation of the great vessels, local hyperthermia, trophic skin disorders, systolic diastolic murmur with an epicenter over the patol area, shunt. General symptoms are: tachycardia, arterial hypertension, pronounced changes in cardiac function. Ulcerative and necrotic processes are constant, often accompanied by bleeding.

Examination of patients reveals pronounced arterialization of venous blood. With arteriography, it is possible to identify the location of the pathol, formations. Characteristic angiographic signs of the defect are: simultaneous filling of the arteries and veins with contrast agent, depletion of the vascular pattern distal to the anastomosis, accumulation of contrast agent in the places of their localization.

Treatment consists of eliminating patol, connections between arteries and veins by ligating and crossing fistulas, removing aneurysms, excision of arteriovenous plexuses within healthy tissues. For diffuse lesions of the vessels of the extremities, the only radical treatment method is amputation.

Damage

Injuries K. s. more common in wartime. Thus, during the Great Patriotic War (1941 -1945), damage to main lines was caused. occurred in 1% of the wounded. Isolated injuries of arteries amounted to 32.9%, and veins - only 2.6%, combinations of damage to arteries and veins - 64.5%. Classification of gunshot wounds K. s. developed during the same period (Table 1). Often, vascular damage is combined with bone fractures and nerve injury, which aggravates the wedge, picture and prognosis.

In peacetime practice, injuries and damage to arteries and veins amount to approx. 15% of all emergency pathology K. s. Most of the damage to K. s. occurs as a result of transport accidents, knife wounds and, less commonly, gunshot wounds.

Arterial injuries are divided into closed and open. Closed injuries to blood vessels, in turn, are divided into contusions, when there is damage only to the inner shell of the vessel, and ruptures, in which damage occurs to all three layers of the wall. When an artery is ruptured or injured, blood spills into the surrounding tissues and a cavity is formed, communicating with the lumen of the vessel (Fig. 25), a pulsating hematoma (see). In case of arterial injuries, pulsation distal to the injury site is weakened or completely absent. In addition, there are phenomena of ischemia of the area supplied by this artery (see Ischemia), and the degree of ischemia can be different, and therefore has a different effect on the fate of the limb (Table 2), up to the development of gangrene (see) .

Each wound to K. s. is accompanied by bleeding (see), which can be primary (at the time of wounding of the vessel or immediately after it), and secondary, which, in turn, is divided into early and late. Early secondary bleeding occurs within the first day after injury and can be a consequence of increased blood pressure, improved blood circulation, etc. Late secondary bleeding, developing after 7 or more days, can occur as a result of wound infection spreading to the wall of the joint. The cause of secondary bleeding can also be foreign bodies close to the wall of the joint.

Diagnosis of damage to main circuits. in most cases it is placed on the basis of a pronounced wedge pattern, especially with lateral wounds. It is more difficult to recognize complete ruptures of the vessel, since screwing in the inner lining of the artery helps to spontaneously stop bleeding, and due to the divergence of the ends of the artery, these injuries are often not recognized even during surgical treatment wounds. The greatest number of diagnostic errors occurs with closed vascular injuries. With such injuries, only the inner and middle membranes of the vessel are often damaged with impaired blood flow, which is not always easy to recognize even when the vessel is inspected during surgery. In some cases, especially with a closed injury, there is a need for arteriography, which allows one to identify the nature, extent and location of the injury, as well as choose the method of surgical treatment and its volume. The diagnosis of spasm or compression of the artery should also be substantiated by arteriography or inspection of the vessel during surgery. wound treatment.

The first measure in the treatment of wounds of K. s. is a temporary stop of bleeding. For this purpose, use a pressure bandage (see), pressing K. with. along with a finger, closing the hole in the wound with fingers inserted into the wound according to N.I. Pirogov, applying a demeure clamp and tamponade of the wound with gauze swabs (see Tamponade). In addition, hemostatic agents can be used general action(10% calcium chloride solution, vitamin K, fibrinogen, etc.).

After using one of the temporary methods to stop bleeding, in most cases there is a need to permanently stop the bleeding. Methods for finally stopping bleeding include: ligation of the artery in the wound or throughout and the application of a vascular suture (see) or patches to the defect in the arterial wall. Two facts should be taken into account, established by domestic surgeons during the Second World War: ligation of the main arteries of the extremities in 50% of cases led to their gangrene, and reconstructive operations, in particular vascular suture, were possible in only 1% of vascular operations.

In peacetime, surgical treatment should be aimed at restoring the main blood flow. An effective reconstructive operation can be performed for K.'s injury. at different times: from several hours to several days. The possibility of surgical intervention should be judged by the condition and changes in tissue in the area of ​​ischemia and damage. Reconstructive operations for trauma to K. s. can be extremely varied. The main type of surgical intervention for damage to the arterial trunks is a manual lateral or circular suture; according to indications, vascular stapling devices are also used (see Stapling devices). With complications of K.'s injury. widespread thrombosis, it is necessary to first perform thrombectomy (see) from the central and distal ends of the damaged artery. In case of combined damage to large arterial and venous trunks, one should strive to restore the patency of both blood vessels. This is especially important in cases of severe ischemia of the limb. Ligation of the main vein in such conditions, even with the restoration of full arterial blood flow, significantly contributes to the reverse development of ischemia and, causing venous blood stasis, can lead to thrombosis in the area of ​​the arterial suture. For arterial injuries accompanied by a large tissue defect, replacement of the arterial defect with a synthetic corrugated prosthesis or autovein is used (Fig. 26 and 27).

Staged treatment

In military field conditions, first medical aid on the battlefield (at the source of the lesion) in cases of external bleeding comes down to temporarily stopping it. Stopping bleeding begins with finger pressure of the vessels in typical places, then a pressure bandage is applied. If bleeding continues, apply a tourniquet (see Hemostatic tourniquet). In the absence of fractures, forced flexion of the limb can be used; the edges should be bandaged to the body.

First aid includes monitoring and changing tourniquets from improvised means to standard ones.

During first medical aid (PMA), wounded people with ongoing bleeding, with bandages soaked in blood, and with tourniquets are sent to the dressing room. The following methods of temporarily stopping bleeding are used: applying a pressure bandage; tamponade of wide wounds, if possible, suturing the edges of the skin over the tampon, followed by applying a pressure bandage; applying a clamp to a vessel visible in the wound and its subsequent dressing; If it is impossible to stop the bleeding using the above methods, apply a tourniquet. A plywood splint wrapped in cotton wool should be placed under the tourniquet on the limb on the side opposite to the location of the vascular bundle. Above the level of application of the tourniquet, local anesthesia is performed (conductor or case blockade). Analgesics are administered. After temporary stopping of bleeding, immobilization is used. When the wounded are admitted with tourniquets, the validity and correctness of their application are checked: a novocaine blockade is performed above the tourniquet, the vessel above the tourniquet is pressed with fingers, the tourniquet is slowly relaxed. If bleeding resumes, you should try to stop it using the listed methods without using a tourniquet; if this fails, then a tourniquet is applied again. All tourniquets from improvised means are replaced with service ones. If, after removing the tourniquet, bleeding does not resume, then a pressure bandage is applied to the wound, and the tourniquet is left loose on the limb (provisional tourniquet). In case of rigor mortis of the limb muscles, removal of the tourniquet is contraindicated.

All wounded with temporarily stopped bleeding must be evacuated first.

With qualified assistance (SMEs), in the process medical triage, the following groups of wounded are identified: with tourniquets applied; with severe blood loss; with uncompensated ischemia; with compensated ischemia.

With a minimal and reduced amount of assistance, wounded people with tourniquets, massive blood loss and uncompensated ischemia of the limb are sent to the dressing room. Anti-shock measures in this group it is usually carried out in parallel with surgical treatment.

With the full scope of assistance, all those admitted with vascular injuries are sent to the dressing room, except for the wounded with compensated ischemia without a history of bleeding, whom it is advisable to send to the hospital base institutions in the first place for assistance.

If a limb is in a state of rigor mortis due to the application of a tourniquet, it is subject to amputation at the level of application of the tourniquet.

When providing qualified assistance, a final stop of bleeding is indicated with restoration of vessel patency by applying a suture (under appropriate conditions).

In conditions of a complex medical and tactical situation, as well as in the absence of surgeons proficient in the vascular suture technique, it is necessary to ligate the vessel in compliance with a number of precautions to avoid gangrene of the limb (see Vascular collaterals, Ligation of blood vessels). Vessel ligation is also permitted for large defects that require lengthy, labor-intensive plastic surgery.

In hospitals, medical treatment is in progress. triage identifies the following categories of wounded: 1) wounded with restored vessels, the Crimea continues treatment, and if indicated, repeat reconstructive operations are performed; 2) wounded with dead limbs, the Crimea determines the level of necrosis and carries out truncation of the limb; 3) wounded with temporarily stopped or spontaneously stopped bleeding, whose vessels were not restored due to the conditions of the situation when providing qualified assistance; they perform reconstructive operations.

Reconstructive operations are contraindicated in the general serious condition of the wounded, with the development of a wound infection, or in the midst of radiation sickness.

Hospitals also operate on wounded people for secondary bleeding, festering hematomas and aneurysms (mostly the vessel is ligated along its length).

Operations for traumatic aneurysms (hematomas), as well as restoration of ligated vessels should be performed as soon as possible. early dates, because subsequently, due to the development of collaterals, the distal section of the damaged vessel sharply narrows, as a result of which restoration of the main blood flow often becomes impossible, while the collaterals are destroyed during excision of the aneurysm and the blood circulation of the limb sharply deteriorates.

When performing operations for damage to vessels of various locations, one should remember a number of anatomical and wedge features, knowledge of which will help to avoid the occurrence of severe complications.

Damage to the subclavian vessels is often combined with trauma brachial plexus, which often leads to diagnostic errors, since disorders of movement and sensitivity due to ischemia are regarded as an injury to the nerve trunks. To avoid massive, difficult-to-stop bleeding, to create good surgical access, it is necessary to cross or resect part of the clavicle during the operation, followed by its implantation.

In case of injuries to the axillary vessels, it is necessary to carefully examine all veins, and ligate the damaged venous trunks in order to avoid air embolism (see) or thromboembolism (see).

The brachial artery has an increased tendency, compared to other arteries, to prolonged spasm, which can sometimes cause no less serious circulatory disorders of the limb than with a complete rupture of the artery. When performing operations on this vessel, the mandatory local use of novocaine and papaverine is necessary.

If one of the arteries of the forearm is injured, there is no need for reconstructive surgery; ligation of the vessel is safe.

Extensive damage iliac arteries most often require alloplasty. It is advisable, in contrast to operations on other segments, to strive to restore the iliac veins, since in this anatomical region there are not always sufficient indirect ways of blood outflow.

Damage to the femoral artery is most dangerous in the area of ​​the adductor (Gunter's) canal and often leads to gangrene of the limb. If the femoral and great saphenous veins are simultaneously damaged, it is necessary to restore one of the venous outflow collectors.

Damage to the popliteal artery in 90% of patients is accompanied by gangrene of the leg. Along with emergency restoration of the artery, it is advisable to restore the damaged vein, since venous stasis contributes to the development of severe ischemic tissue edema, which can cause repeated ischemia after restoration of arterial patency. To avoid this complication, restoration of the popliteal vessels with uncompensated ischemia should end with dissection fascial sheaths calf muscles.

Damage to the arteries of the leg is usually accompanied by a spasm that spreads to the entire arterial network of the segment. In such cases, the use of antispasmodics is indicated, and in case of unremovable spasm, fasciotomy is indicated.

The literature discusses the technique of temporary vascular prosthetics, which, according to some authors, can allow vascular restoration to be carried out in two stages: at the stage of qualified assistance, the resumption of blood flow using a temporary prosthesis and at the stage of specialized care, the final restoration of the vessel. It is difficult to count on the successful implementation of this method, since exposure of the damaged ends of the vessel and their treatment for effective prosthetics require such a degree of qualification of the surgeon, which allows the restoration of the vessel. In addition, temporary prosthetics during a long evacuation can be complicated by thrombosis of the prosthesis, the end of the prosthesis falling out of the vessel and the resumption of bleeding. However, temporary prosthetics is undoubtedly an advisable measure during a reconstructive operation, since it allows you to reduce the duration of ischemia and restore normal color tissues and provide more radical treatment of the wound.

(see), post-thrombotic disease, varicose veins (see). IN surgical practice Most often, patients suffer from atherosclerotic lesions of the aorta and large main arteries of the extremities, as well as organ vessels (renal, mesenteric and celiac arteries). Damage to the main arteries of the extremities is accompanied by ischemia of the corresponding area, characterized by pallor of the skin, pain, limited mobility and trophic disorders, turning in some cases into gangrene (see).

Narrowing of the carotid arteries leads to cerebral ischemia. The severity of the disease and its prognosis depend on which particular artery is excluded from the blood flow, as well as on the degree of development of collateral circulation.

Narrowing of the renal artery due to atherosclerosis, arteritis or fibromuscular dysplasia is accompanied by persistent arterial hypertension (see Arterial hypertension), which is sometimes malignant in nature (renovascular hypertension) and is not amenable to conservative treatment.

The narrowing of the mesenteric vessels is accompanied by a clinical picture of abdominal sore throat with sharp abdominal pain and dyspeptic disorders (see. Abdominal angina).

Acute thrombosis or embolism of the arterial trunks of the extremities or the terminal aorta is accompanied by signs of acute ischemia of the extremities. Embolism is more often observed in women, acute thrombosis - in men due to their greater susceptibility to atherosclerotic damage to the arteries. Acute thrombosis and embolism most often affect the aortic bifurcation and vessels of the lower extremities; The vessels of the upper extremities are much less frequently affected.

Postthrombotic disease is a disease that develops as a result of thrombosis of deep venous lines. Morfol, its basis is structural lesions of the deep veins in the form of re-canalization or occlusion. In the pathogenesis of post-thrombotic disease, disturbances in the venous return of blood due to perverted blood flow through deep, perforating and superficial veins, microcirculatory changes and insufficiency of lymph circulation play a role. According to the wedge, the picture distinguishes between edematous, edematous-varicose, varicose-trophic and trophic forms. There are stages of compensation, sub-compensation and decompensation. The diagnosis is made on the basis of anamnestic data, wedge, symptoms and venographic studies. The course is chronic. Indications for surgical treatment are trophic changes in the skin and secondary varicose veins of the superficial veins, subject to recanalization of the deep veins of the leg. It consists of total or subtotal ligation of perforating veins of the leg, supplemented by removal of only varicose veins. Segmental lesions of the iliac and femoral veins may be an indication for bypass surgery and replacement surgery for the edematous form of the disease. Regardless of the operation performed, you must continue conservative treatment; physiotherapeutic procedures, elastic compression, drug therapy, san.-kur. treatment.

Tumors

Tumors (angiomas) have the same structure as vessels - arteries, veins, capillaries, or are derived cells that form special structures in the vascular walls.

Vascular tumors occur at any age, regardless of gender. Their localization is different: skin, soft fabrics, internal organs, etc. In the development of vascular tumors, great importance is attached to dysembryoplasia in the form of detachments of angioblastic elements, which in the embryonic period or after birth begin to proliferate, forming malformed vessels of different structures. Tumors develop on the basis of these dysembryoplasias or without connection with them.

There are benign tumors: hemangioma (see), endothelioma (see), differentiated hemangiopericytoma (see), glomus tumors (see), angiofibroma (see) and malignant: malignant angioendothelioma (see), malignant (undifferentiated) hemangiopericytoma .

Wedge, manifestations depend on the size and location of the tumor. Malignant tumors give hematogenous metastases.

Treatment is surgical, cryotherapy, radiation.

Operations

In the 20th century vascular surgery is achieving significant success, which is associated with the introduction of special instruments into practice, improvement of the vascular suture (see), the development of radiopaque research methods, and the creation of specialized institutions. Common to all operations on blood vessels, in addition to the usual conditions necessary for any intervention, are measures to prevent bleeding and other dangerous consequences - thrombosis of blood vessels, ischemic changes in the tissues of a limb, organ, or area of ​​the body that are supplied with blood through a given vascular line. In this regard, the method of preparing the patient for surgery and the features of postoperative management become of great importance. Dangerous consequences of blood loss are prevented by blood transfusion (see) into a vein or artery. Therefore, during each operation on K. s. it is necessary to have a supply of canned blood and blood-substituting fluids (see).

Since, along with the dangers of bleeding and the consequences of blood loss (see) during operations on K. s. It is possible that a blood clot may occur in the lumen of the vessel and embolism; it is necessary to determine blood coagulation parameters before and after surgery. In case of increased blood clotting, anticoagulants should be prescribed in the preoperative period.

During operations on K. s. Various methods of pain relief are used, but most often inhalation anesthesia (see). Used for special indications

Rice. 28. Schematic representation of operations to restore the main blood flow in case of segmental occlusion of arteries: a - bypass; b - endarterectomy; c - resection of a blocked segment of the artery with its prosthetics (1 - section of the artery blocked by a thrombus, 2 - graft, 3 - dissected section of the artery, 4 - removed section of the artery).

Indications for operations on K. s. are varied, but the indications for arterial operations are most often segmental occlusions of arteries with vessel patency above and below the site of blockage. Other indications are wounds of blood vessels, their tumors, varicose veins, pulmonary embolism, etc. Restoration of the main blood flow is achieved through operations of resection of a blocked segment of the artery with its prosthetics, bypass surgery and endarterectomy (Fig. 28).

For prosthetics of K. s. autovein and synthetic prostheses are widely used. The disadvantage of the autovein is its low suitability for prosthetics of large-caliber arteries due to the lack of veins of the appropriate diameter that could be resected without much damage to the body. In addition, gistol, studies in long-term postoperative period showed that the autovenous vein sometimes undergoes connective tissue degeneration, which can cause thrombosis of the vessel or the formation of an aneurysm.

The use of synthetic prostheses has fully justified itself in the prosthetics of the aorta and large-diameter arteries. When replacing arterial vessels of smaller diameter (femoral and popliteal arteries), the results were significantly worse, since in these areas there are more favorable conditions for the occurrence of thrombosis. In addition, the lack of proper elasticity and extensibility of the prosthesis leads to frequent thrombosis, especially if the graft crosses the joint line.

Another type of intervention aimed at restoring the main blood flow is endarterectomy. The first endarterectomy was performed by R. Dos Santos (1947). Endarterectomy methods can be divided into closed, semi-open and open. The method of closed endarterectomy consists in the fact that the operation is performed with a special instrument from a transverse incision of the artery. A semi-open endarterectomy is the removal of the inner lining through several transverse incisions in the artery. Open endarterectomy involves removing the altered inner membrane through a longitudinal arteriotomy above the site of occlusion.

Endarterectomy using the eversion method has been introduced into practice, the essence of which is that after isolating the artery and crossing distal to the site of occlusion with a special tool, atherosclerotic plaques are peeled off along with the altered inner membrane, the outer and middle membranes are turned inside out to the end of the plaque. After this, the artery is screwed back in again and anastomosed with a circular manual or mechanical suture. The indication for this method of endarterectomy is segmental atherosclerotic occlusion of minor extent.

For widespread atherosclerotic occlusions without pronounced destruction of the vessel walls, endarterectomy is performed using the eversion method, followed by reimplantation of the vessel. In this case, the entire affected area of ​​the arterial trunk is resected. Next, endarterectomy is performed using the eversion method. After screwing the artery back in, the formed autograft is checked for leaks and is sutured end to end in two anastomoses in its original place.

A significant extent of occlusion with wall destruction (calcification, ulcerative atheromatosis), arteritis or vessel hypoplasia are indications for autotransplantation with explantation. With this method, a graft consisting of a synthetic prosthesis is used, and in places of fiziol, folds, for example, under the inguinal ligament, an autoartery is located. The main advantage of this method is that in the place of greatest trauma to the vessel (hip, knee, shoulder joints) it is not the alloprosthesis that passes through, but the autoartery.

Issues of surgical treatment of arterial hypertension associated with occlusive lesions of the renal arteries are being widely developed. The choice of surgical intervention for this disease depends on the cause and nature of the lesion. The method of transaortic endarterectomy is applicable only for atherosclerosis, when there is segmental damage to the mouth of the renal arteries. Since atherosclerosis is the most common cause renovascular hypertension, then this method finds the most wide application. In fibromuscular dysplasia, since patol, the process can be of a varied nature (tubular, multifocal, etc.), the range of surgical interventions is much wider and includes autoarterial replacement of the renal artery, its resection with end-to-end anastomosis and reimplantation of the mouth of the renal artery. In case of widespread damage to the renal artery due to arteritis, the most appropriate operations remain renal artery resection with its replacement and aortorenal bypass surgery. An autoarterial graft from the deep femoral artery is used as a plastic material.

Reconstructive operations on the branches of the aortic arch are one of the new and unique types of vascular surgery. The most accessible surgical corrections are segmental occlusions located in the proximal parts of the arterial bed. The main type of reconstruction for both stenosis and complete blockages of the brachiocephalic branches is endarterectomy.

Resection of the affected area of ​​the artery with its plastic surgery is permissible only in the initial parts of the innominate, common carotid and subclavian arteries(before branches depart from them). For the success of surgical treatment of this pathology, it is of great importance right choice surgical access to the branches of the aortic arch.

Methods of operations on veins and their features are given in special articles (see Varicose veins, Ligation of blood vessels, Thrombophlebitis, Phlebothrombosis).

In the postoperative period, the most important measures are the prevention of inflammatory complications, thrombosis and embolism. Anticoagulants (most often heparin) are used 24 hours after surgery. Heparin is administered intravenously at a dose of 2500-3000 units every 4 hours. within 3-5 days. It is advisable to maintain the Bürker blood clotting time within 7-8 minutes.

Results of surgical treatment of wounds and diseases of K. s. generally favorable.

In the treatment of congenital anomalies K. s. (aneurysms, arteriovenous anastomosis), mortality and ischemic complications are almost non-existent, which is associated with adequate development of collateral circulation in these cases and well-developed methods of surgical interventions.

Results of surgical treatment of benign tumors of K. s. depend on the location and extent of the lesion. In some cases, complete cure of extensive cutaneous hemangiomas cannot be achieved. Surgical treatment of malignant angiomas cannot be considered satisfactory due to rapid growth, recurrence and metastasis. The results of treatment of endarteritis depend on the severity of the process. Treatment of thrombophlebitis due to the introduction of active anticoagulants and the improvement of surgical techniques has improved significantly.

Further progress in vascular surgery largely depends on the introduction into practice of new methods for the early diagnosis of diseases of blood vessels. and improvement of surgical methods of treatment, and primarily microsurgery (see).

Tables

Table 1. CLASSIFICATION OF GUNSHOT WOUNDS OF VESSELS BY TYPE OF DAMAGED VESSEL AND BY CLINICAL NATURE OF THE WOUND (from the book “The Experience of Soviet Medicine in the Great Patriotic War of 1941 - 1945”)

1. Injury to the artery	a) without primary bleeding and pulsating hematoma (vascular thrombosis) b) accompanied by primary arterial bleeding c) with the formation of a pulsating arterial hematoma (aneurysm)
2. Vein injury	a) without primary bleeding and hematoma (vascular thrombosis) b) accompanied by primary venous bleeding c) with the formation of a venous hematoma
3. Injury to an artery along with a vein	a) without primary bleeding and pulsating hematoma (vascular thrombosis) b) accompanied by primary arteriovenous bleeding c) with the formation of a pulsating arteriovenous hematoma (aneurysm)
4. Severance or crushing of a limb with damage to the neurovascular bundle

Table 2. CLASSIFICATION, DIAGNOSTICS, PROGNOSIS AND TREATMENT OF ISCHEMIA IN VASCULAR INJURIES OF THE LIMB (according to V. A. Kornilov)

Degree of ischemia	Main clinical signs
Compensated (due to bypass blood flow)	Active movements, tactile and pain sensitivity are preserved	There is no threat of gangrene of the limb	There are no indications for urgent vessel restoration. Vessel ligation is safe
Uncompensated (circulatory blood flow is insufficient)	Loss of active movements, tactile and pain sensitivity occurs 72 - 1 hour after injury	The limb will become dead over the next 6-10 hours.	Emergency vessel repair is indicated
Irreversible	Rigor mortis of the limb muscles develops	Gangrene of the limbs. Limb preservation is not possible	Amputation is indicated. Vessel repair is contraindicated - death from toxemia is possible

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B. V. Petrovsky, M. D. Knyazev, V. S. Savelyev; I. I. Deryabin, V. A. Kornilov (military), Yu. F. Isakov, Yu. A. Tikhonov (det. surgeon), V. V. Kupriyanov (an.), I. G. Olkhovskaya ( onc.), N. E. Yarygin (pat. an.).