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The main human joints, their characteristics. Classification of joints according to the shape of the articular surfaces, the number of axes and function

make movements relative to each other using muscles. Joints are located in the skeleton where distinct movements occur: flexion (lat. flexio) and extension (lat. extensio), abduction (lat. abductio) and casting (lat. adductio), pronation (lat. pronatio) and supination (lat. supinatio), rotation (lat. circumflexio). As an integral organ, the joint takes an important part in supporting and motor functions. All joints are divided into simple, formed by two bones, and complex, which is an articulation of three or more bones.

Structure

Each joint is formed by the articular surfaces of the epiphyses of bones, covered with hyaline cartilage, an articular cavity containing large number synovial fluid, joint capsule and synovium. In the cavity of the knee joint there are menisci - these cartilaginous formations increase congruence (compliance) articular surfaces and are additional shock absorbers that soften the impact of shocks.

Main elements of the joint:

  • joint cavity;
  • epiphyses of bones forming a joint;

Articular surfaces

Articular surfaces(lat. facies articulares) articulating bones are covered with hyaline (less often fibrous) articular cartilage 0.2-0.5 mm thick. Constant friction maintains smoothness, facilitating the sliding of the articular surfaces, and the cartilage itself, thanks to its elastic properties, softens shocks, acting as a buffer.

Joint capsule

Articular cavity

Articular cavity- a slit-like hermetically sealed space limited by the synovial membrane and articular surfaces. The articular cavity of the knee joint contains the menisci.

Periarticular tissues

Periarticular tissues- these are the tissues directly surrounding the joint: muscles, tendons, ligaments, blood vessels and nerves. They are sensitive to any internal and external negative influences; disturbances in them immediately affect the condition of the joint. The muscles surrounding the joint provide direct movement of the joint and strengthen it from the outside. Numerous nerve pathways, blood vessels and lymphatic vessels, nourishing the joints.

Joint ligaments

Joint ligaments- strong, dense formations that strengthen the connections between bones and limit the range of motion in the joints. Ligaments are located on the outside of the joint capsule; in some joints (knee, hip) they are located inside to provide greater strength.

The blood supply to the joint is carried out from a widely anastomosing (branched) articular arterial network formed by 3-8 arteries. The joint is innervated by its nervous network formed by sympathetic and spinal nerves.

All articular elements (except for hyaline cartilage) have innervation, in other words, they contain significant numbers of nerve endings that, in particular, carry out pain perception, and therefore can become a source of pain.

Classification of joints

According to the current anatomical and physiological classification, joints are distinguished:

  • By number of articular surfaces
  • By the shape of the articular surfaces and functions.

By number of articular surfaces:

  • simple joint (lat. articulatio simplex) - has two articular surfaces, for example the interphalangeal joint thumb;
  • compound joint (lat. articulatio composite) - has more than two articular surfaces, for example the elbow joint;
  • complex joint (lat. articulatio complexa) - contains intra-articular cartilage (meniscus or disc), dividing the joint into two chambers, for example the knee joint;
  • combined joint- a combination of several isolated joints located separately from each other, for example the temporomandibular joint.

By function and shape of articular surfaces.

  • Uniaxial joints:
  1. Cylindrical joint (lat. cylindrica), for example atlanto-axial median;
  2. Trochlear joint (lat. ginglymus), for example interphalangeal joints of the fingers;
  3. A helical joint is a type of trochlear joint, for example the humeroulnar joint.
  • Biaxial joints:
  1. Elliptical (lat. ellipsoidea), for example the wrist joint;
  2. Condylar (lat. condylaris), for example the knee joint;
  3. Saddle-shaped (lat. sellaris), for example, the carpometacarpal joint of the first finger;
  • Multi-axis joints:
  1. Globular (relative to the long axis of the articulating bones.

    Elliptical joint- articular surfaces have the form of ellipse segments (one convex and the other concave), which provide movement around two mutually perpendicular axes.

    Condylar joint- has a convex articular head, in the form of a protruding process (condyle), close in shape to an ellipse. The condyle corresponds to a depression on the articular surface of another bone, although their surfaces may differ significantly from each other. The condylar joint can be considered as a transitional form from the trochlear joint to the ellipsoid joint.

    Saddle joint- formed by two saddle-shaped articular surfaces sitting “astride” each other, one of which moves along the other, making movement in two mutually perpendicular axes possible.

    Ball and socket joint- one of the articular surfaces is represented by a convex spherical head, and the other is a correspondingly concave articular cavity. Theoretically, movement in this type of joint can be carried out around many axes, but in practice only three are used. The ball and socket joint is the loosest of all joints.

    Flat joint- have practically flat articular surfaces (a ball surface with a very large radius), so movements are possible around all three axes, but the range of movements due to the slight difference in the areas of the articular surfaces is insignificant.

    Tight joint (amphiarthrosis) - represent a group of joints with different shapes of articular surfaces with a tightly stretched capsule and a very strong auxiliary ligamentous apparatus; closely adjacent articular surfaces sharply limit the range of movements in this type of joint. Tight joints smooth out shocks and soften shocks between bones


In sports morphology, two main indicators of joints are of interest: possible movement around three mutually perpendicular axes and the strengthening apparatus. A joint is a kinematic joint consisting of two or more articulating bony surfaces (Fig. 5.2). All joints are usually divided into simple, when two articular surfaces of different shapes are connected in one articular capsule (spherical, ellipsoidal, cylindrical and their variety - block-shaped, as well as flat).

Complex – The articular capsule connects several articular surfaces belonging to individual bones.

Complex- in the articular capsule two or more articular surfaces are connected, but between them an articular layer is inserted in the form of a crescent (meniscus) or a disk that divides the joint cavity into two independent chambers (double-chamber joints). Instead of cartilaginous formations, there may be intra-articular ligaments that hold the bones next to each other and do not allow them to move sharply to the side during movements.

Combined joints – these are two simple joints combined into one kinematic chain. An example is the right and left temporomandibular joints.

In joints, it is customary to distinguish the following ligaments by function: retaining ligaments - which do not allow the bones to move to the sides; guides - lateral ligaments that direct movement in one plane - this is, as a rule, a thickening of the joint capsule.

The coach needs to know the axes and planes of possible movements in the joints and explain them to novice athletes to prevent injuries. Beginning wrestlers especially often injure the elbow joint by hyperextending it, not knowing that extension at the elbow joint should not exceed 180°.

The joint capsule is a complex morphological combination of coarse adhesive (collagen) fibers, elastin and loose connective tissue, which form a dense filter with many complex functions - from mechanical to analytical, signaling to the central nervous system about the stretching of the capsule, and therefore the position of the joint. The capsule is penetrated by nerve trunks, which are divided into the thinnest nerves with specialized nerve endings. In the joint capsule, as it deepens towards its internal synovial membrane, there are blood vessels(arteries and veins), ending in the villi of the synovial membrane with complex capillary networks. Villi have a trophic role (inflow and outflow of blood).

The sternoclavicular joint.

A complex saddle-shaped joint with an intra-articular disc dividing the articular cavity into two chambers (Fig. 5.3)

The joint is strengthened by three ligaments: the sternoclavicular anterior and posterior and interclavicular. Allows movement in all three axes. Movement around the vertical axis forward and backward, movement around the sagittal axis up and down laterally and rotational movements around the frontal axis with a sharp movement in the shoulder joint:
flexion and extension. This joint actively works in weightlifters when lifting the barbell, in throwers, and in tennis players.

Shoulder joint.

It is sometimes called scapulohumeral (Fig. 5.4). The joint is simple, spherical in shape with an intra-articular cartilaginous lip surrounding the glenoid cavity on the scapula. It does not have ligaments like other joints, but is surrounded by a group of skeletal muscles and tendons that strengthen the joint. Overhanging the articular head are the coracoid and acromial processes of the scapula, which are connected by the acromiocoracoid ligament, which forms a vault above the joint.

This structure of the joint creates the opportunity, under heavy loads (gymnastics, wrestling), to dislocate the head of the humerus forward, backward, downwards, but upward dislocation is never observed without fractures of the acromion and coracoid process. A special feature of the joint is its free capsule, which is attached to the scapular neck (behind the labrum) and to the anatomical neck of the humerus. This allows for extensive movement around the major axes in the joint. Existing protrusions of the synovial membrane along the tendon of the long head of the biceps muscle and under the subscapularis muscle in children can be pinched and cause pain. The shoulder joint is additionally strengthened by the tendons of the subscapularis muscle, from above - by the supraspinatus muscle, and from behind - by the infraspinatus and teres minor muscles. These tendons are called the “rotator cuff.” This joint strengthening works especially effectively when performing todes in figure skating. In the training process, first of all, special and strengthening exercises for these tendons and muscles should be used.

Between the head of the humerus, the supraspinatus tendon and the acromial process there is a synovial subacromial bursa, which in young athletes can be pinched and be the basis of long-term pain.

Elbow joint.

A complex joint that combines three joints in one articular capsule, together having two axes of movement. The humeroulnar, humeroradial and ulnoradial joints are united. According to the nature of their movement, they are classified as a trochlear joint, that is, uniaxial. Bursa The joint is attached superiorly along the semilunar notch of the ulna and neck of the radius. On the outer and inner sides, the capsule thickens, forming the lateral radial and ulnar ligaments. In case of injury, these ligaments fit tightly to the bones and divide the joint into two chambers: anterior and posterior.

Hip joint.

A combined joint, represented by a round head of the femur, a cup-shaped acetabulum, complemented by a cartilaginous articular lip. It is classified as a nut-shaped joint, since the head of the femur is tightly covered by the articular lip. This joint bears a large weight load, but nevertheless has a wide range of motion. The joint is biomechanically extremely stable, which is determined by: 1) the deep position of the femoral head in the acetabulum; 2) a strong and dense articular capsule; 3) powerful muscles surrounding the joint, the tendons of which are attached over a fairly wide space from the middle of the femoral neck to the intertrochanteric tuberosity and line.

The acetabulum is fused from the bodies of three bones - the ilium, the ischium and the pubis. The upper and posterior surfaces of the glenoid cavity are thickened and very strong, since they bear the main force of gravity of the body.

The ligamentous apparatus of the joint is structured in a very unique way (Fig. 5.5). The ligaments coming from the pelvic bones intertwine and form a fibrous ring surrounding the neck of the femur, which is smaller in diameter than the head. The ligaments woven into this ring “attract” femur to the acetabulum. The strength of the ligaments can withstand pressure of 500 kg, and the closure of the capsule and the fluid wetting the articular surfaces have the effect of additionally holding the bones tightly to one another.

The three bursae located around the joint allow the muscles surrounding the joint to move without friction.

Sports morphologists and medical workers you should pay attention to the ratio bone formations pelvis and thighs between each other, as these are signs of underlying inflammatory processes or consequences of injuries. Gait is of particular importance. Changing it hidden reasons injuries Deviations (not always permanent) in gait are observed in girls when they ineptly learn exercises such as transverse and longitudinal splits.

The trainer should pay attention to deviations in mobility during hip abduction and extension. Sometimes these are the first symptoms of disorders associated with incipient microtraumas of the tendons and ligaments surrounding the joint. Deviation in the lines connecting the anterosuperior iliac spines and the main lines lower limbs, talk about asymmetrical development of the lengths of the lower extremities. A number of developmental deficiencies or pain during movement are compensated by curves of the lumbar spine, asymmetrical placement of the feet, etc.

Knee joint.

This is the largest of all joints with features of embryonic anlage and subsequent development (Fig. 5.6). It refers to complex condylar joints with additional intra-articular formations - menisci, ligaments. The joint capsule is dense, but not very stretched between the bones that form the joint. The joint capsule is further strengthened by the tendons and ligaments of the joint itself, as well as in front by the tendon of the quadriceps femoris muscle. These ligaments and connective tissue fibers of the outer joint capsule are often injured during tackles by football players, slalomists, and wrestlers during a painful hold. The joint is also strengthened cruciate ligaments, which lie outside the joint capsule and are covered with synovial membrane. Early barbell training and sudden low squats cause injuries to these ligaments. According to experienced sports doctors and trainers, to develop the quadriceps femoris muscle, it is not at all necessary to perform deep squats, up to 90-80° is enough. When squatting, the anterior cruciate ligament is injured.

The medial and lateral menisci are wedge-shaped (in a vertical section). The wide side of the meniscus is attached along the entire periphery to the joint capsule. The inner thin edge faces the inside of the joint and is free. In front, the menisci are connected by a ligament. Their upper surface is concave corresponding to the convexity of the condyles of the femur, the lower surface is smooth and adjacent to the condyles of the tibia. It should be noted that there is a congenital sloping of the upper surface of the tibia, which is fraught with injuries when playing sports, even such as volleyball (attack kick). There are seven synovial bursae around the knee joint that can be injured. The causes of frequent injuries to the knee joint are O-shaped and X-shaped lower limbs. For example, this shape of the legs is one of the main reasons for refusing to engage in parachuting.

Ankle joint.

A typical trochlear joint formed by the talus, its trochlea and the “fork” formed by the fibula and tibia, and their ankles. The joint capsule extends from the tibia more anteriorly than posteriorly. The capsule itself is thin, but it is strengthened by a powerful ligamentous apparatus, both on the medial and lateral sides. The ligaments almost merge into a single formation. The main directions of fibers are identified. Talofibular anterior and posterior and fibulocalcaneal. Among the ligaments one can distinguish short, constantly working fibers and weakly tensioned ones - crimped ones. In case of injury, straight fibers are torn, but long fibers are preserved, as if holding bones during habitual dislocations. On the medial side there is also a powerful ligamentous apparatus. If supination and dislocation of the foot are a common phenomenon against the background of tired muscles, then pronation and dislocation are rare.

Around the ankle joint, fascial retinaculum of the muscles descending from the lower leg is formed.



Joint represents a discontinuous, cavity, movable connection, or articulation, articulatio synovialis (Greek arthron - joint, hence arthritis - inflammation of the joint).

In each joint, there are articular surfaces of the articulating bones, an articular capsule that surrounds the articular ends of the bones in the form of a coupling, and an articular cavity located inside the capsule between the bones.

Articular surfaces, facies articulares, covered with articular cartilage, cartilago articularis, hyaline, less often fibrous, 0.2-0.5 mm thick. Due to constant friction, articular cartilage becomes smooth, facilitating the sliding of articular surfaces, and due to the elasticity of the cartilage, it softens shocks and serves as a buffer. The articular surfaces are usually more or less consistent with each other (congruent). So, if the articular surface of one bone is convex (the so-called articular head), then the surface of the other bone is correspondingly concave (the glenoid cavity).

Articular capsule, capsula articularis, hermetically surrounding the articular cavity, grows to the articulating bones along the edge of their articular surfaces or slightly retreating from them. It consists of an outer fibrous membrane, membrana fibrosa, and an inner synovial membrane, membrana synovialis.

The synovial membrane is covered on the side facing the articular cavity with a layer of endothelial cells, as a result of which it has a smooth and shiny appearance. It secretes sticky transparent synovial fluid into the joint cavity - synovia, the presence of which reduces friction of the articular surfaces. The synovial membrane ends at the edges of the articular cartilages. It often forms small processes called synovial villi, villi synovidles. In addition, in some places it forms synovial folds, sometimes larger, sometimes smaller, plicae synovidles, moving into the joint cavity. Sometimes synovial folds contain a significant amount of fat growing into them from the outside, then the so-called fat folds, plicae adiposae, are obtained, an example of which is the plicae alares of the knee joint. Sometimes, in thin places of the capsule, bag-like protrusions or inversions of the synovial membrane are formed - synovial bursae, bursae synovidles, located around the tendons or under the muscles lying near the joint. Being made of synovium, these bursae reduce friction of tendons and muscles during movement.

Articular cavity, сavitas articularis, represents a hermetically closed slit-like space, limited by the articular surfaces and the synovial membrane. Normally it is not free cavity, and is made by synovial fluid, which moisturizes and lubricates the articular surfaces, reducing friction between them. In addition, synovium plays a role in fluid exchange and in strengthening the joint due to the adhesion of surfaces. It also serves as a buffer, softening compression and shock of the articular surfaces, since movement in the joints is not only sliding, but also divergence of the articular surfaces. There is negative pressure (less than atmospheric) between the articular surfaces. Therefore, their divergence is prevented by atmospheric pressure. (This explains the sensitivity of the joints to fluctuations in atmospheric pressure in some diseases, which is why such patients can predict worsening weather.)

When the joint capsule is damaged, air enters the joint cavity, causing the articular surfaces to immediately separate. Under normal conditions, divergence of articular surfaces, except negative pressure in the cavity, ligaments (intra- and extra-articular) and muscles with sesamoid bones embedded in the thickness of their tendons also prevent.

Ligaments and tendons of muscles make up the auxiliary strengthening apparatus of the joint. In a number of joints there are additional devices that complement the articular surfaces - intra-articular cartilage; they consist of fibrous cartilage tissue and look like either solid cartilaginous plates - discs, disci articulares, or non-solid, crescent-shaped formations and therefore called menisci, menisci articulares (meniscus, Latin - crescent), or in the form of cartilaginous rims, labra articularia (articular lips). All these intra-articular cartilages along their circumference grow together with the articular capsule. They arise as a result of new functional requirements as a reaction to the complication and increase in static and dynamic loads. They develop from the cartilage of the primary continuous joints and combine strength and elasticity, resisting shock and promoting joint movement.

Biomechanics of joints. In the living human body, joints play a triple role:

  1. they help maintain body position;
  2. participate in the movement of body parts in relation to each other and
  3. are organs of locomotion (movement) of the body in space.

Since during the process of evolution the conditions for muscular activity were different, joints of different forms and functions were obtained.

In shape, the articular surfaces can be considered as segments of geometric bodies of revolution: a cylinder rotating around one axis; an ellipse rotating around two axes, and a ball rotating around three or more axes. At the joints, movements occur around three main axes.

The following types of joint movements are distinguished:

  1. Movement around the frontal (horizontal) axis - flexion (flexio), i.e. decreasing the angle between the articulating bones, and extension (extensio), i.e. increasing this angle.
  2. Movements around the sagittal (horizontal) axis - adduction (adductio), i.e. approaching the median plane, and abduction (abductio), i.e. moving away from it.
  3. Movements around the vertical axis, i.e. rotation (rotatio): inward (pronatio) and outward (supinatio).
  4. Circular movement (circumductio), in which a transition is made from one axis to another, with one end of the bone describing a circle, and the entire bone - the figure of a cone.

Sliding movements of the articular surfaces are also possible, as well as moving them away from each other, as is, for example, observed when stretching the fingers. The nature of movement in the joints is determined by the shape of the articular surfaces. The amount of movement in the joints depends on the difference in the size of the articulating surfaces. If, for example, the glenoid fossa is an arc of 140° in length, and the head is 210°, then the arc of movement will be equal to 70°. The greater the difference in the areas of the articular surfaces, the greater the arc (volume) of movement, and vice versa.

Movements in the joints, in addition to reducing the difference in the areas of the articular surfaces, can also be limited by various types of brakes, the role of which is played by certain ligaments, muscles, bone protrusions, etc. Since increased physical (strength) load causes working hypertrophy of bones, ligaments and muscles , leads to the growth of these formations and limitation of mobility, then different athletes have different flexibility in the joints depending on the type of sport. For example, shoulder joint has a greater range of motion in track and field athletes and a smaller range of motion in weightlifters.

If the braking devices in the joints are especially strongly developed, then movements in them are sharply limited. Such joints are called tight. The amount of movement is also influenced by intra-articular cartilage, which increases the variety of movements. Thus, in the temporomandibular joint, which in terms of the shape of the articular surfaces is classified as a biaxial joint, due to the presence of an intra-articular disc, three types of movements are possible.

Classification of joints can be carried out according to the following principles:

  1. by the number of articular surfaces,
  2. according to the shape of the articular surfaces and
  3. by function.

Based on the number of articular surfaces, they are distinguished:

  1. Simple joint (art. simplex) having only 2 articular surfaces, for example interphalangeal joints.
  2. Complex joint (art. composite) having more than two articulating surfaces, for example the elbow joint. A complex joint consists of several simple joints in which movements can be performed separately. The presence of several articulations in a complex joint determines the commonality of their ligaments.
  3. Complex joint (art. complexa), containing intra-articular cartilage that divides the joint into two chambers (bicameral joint). Division into chambers occurs either completely if the intra-articular cartilage has the shape of a disc (for example, in the temporomandibular joint), or incompletely if the cartilage takes the shape of a semilunar meniscus (for example, in the knee joint).
  4. Combined joint is a combination of several isolated joints, located separately from each other, but functioning together. These are, for example, both temporomandibular joints, proximal and distal radioulnar joints, etc. Since a combined joint represents a functional combination of two or more anatomically separate joints, this differs from complex and complex joints, each of which, being anatomically unified, composed of functionally different compounds.

By form and by function classification is carried out as follows.

The function of a joint is determined by the number of axes around which movements occur. The number of axes around which movements occur in a given joint depends on the shape of its articular surfaces. For example, the cylindrical shape of a joint allows movement only around one axis of rotation. In this case, the direction of this axis will coincide with the axis of location of the cylinder itself: if the cylindrical head is vertical, then the movement occurs around the vertical axis (cylindrical joint); if the cylindrical head lies horizontally, then the movement will occur around one of the horizontal axes coinciding with the axis of the head, for example, the frontal one (trochlear joint). In contrast, the spherical shape of the head makes it possible to rotate around multiple axes that coincide with the radii of the ball (ball-and-socket joint). Consequently, there is complete correspondence between the number of axes and the shape of the articular surfaces: the shape of the articular surfaces determines the nature of the movements of the joint and, conversely, the nature of the movements of a given joint determines its shape (P.F. Lesgaft).

We can outline the following unified anatomical and physiological classification of joints.

Uniaxial joints.

Cylindrical joint, art. trochoidea. A cylindrical articular surface, the axis of which is located vertically, parallel to the long axis of the articulating bones or the vertical axis of the body, provides movement around one vertical axis - rotation, rotatio; such a joint is also called a rotational joint.

Trochlear joint, ginglymus(example - interphalangeal joints of the fingers). Its trochlear articular surface is a transversely lying cylinder, the long axis of which lies transversely, in frontal plane, perpendicular to the long axis of the articulating bones; therefore, movements in the trochlear joint are performed around this frontal axis (flexion and extension). The guide grooves and ridges present on the articulating surfaces eliminate the possibility of lateral slippage and promote movement around a single axis.

If the guide groove of the block is not perpendicular to the axis of the latter, but at a certain angle to it, then when it is continued, a helical line is obtained. Such a trochlear joint is considered to be a screw-shaped joint (for example, the shoulder-ulnar joint). The movement in the helical joint is the same as in the pure trochlear joint. According to the patterns of arrangement of the ligamentous apparatus, in a cylindrical joint the guide ligaments will be located perpendicular to the vertical axis of rotation, in a trochlear joint - perpendicular to the frontal axis and on its sides. This arrangement of ligaments holds the bones in their position without interfering with movement.

Biaxial joints.

Ellipsoid joint, articuldtio ellipsoidea(example - wrist joint). The articular surfaces represent segments of an ellipse: one of them is convex, oval in shape with unequal curvature in two directions, the other is correspondingly concave. They provide movements around 2 horizontal axes, perpendicular to each other: around the frontal - flexion and extension, and around the sagittal - abduction and adduction. Ligaments in elliptical joints are located perpendicular to the axes of rotation, at their ends.

Condylar joint, articulatio condylaris(example - knee joint). The condylar joint has a convex articular head in the form of a protruding rounded process, close in shape to an ellipse, called the condyle, condylus, which is where the name of the joint comes from. The condyle corresponds to a depression on the articular surface of another bone, although the difference in size between them can be significant.

The condylar joint can be considered a type of ellipsoidal joint, representing a transitional form from the trochlear joint to the ellipsoidal joint. Therefore, its main axis of rotation will be the frontal one. The condylar joint differs from the trochlear joint in that there is a large difference in size and shape between the articulating surfaces. As a result, in contrast to the trochlear joint, movements around two axes are possible in the condylar joint. It differs from the ellipsoid joint in the number of articular heads.

Condylar joints always have two condyles, located more or less sagittally, which are either located in the same capsule (for example, the two femoral condyles involved in the knee joint), or are located in different articular capsules, as in the atlanto-occipital joint. Because the heads in the condylar joint do not have a regular elliptical configuration, the second axis will not necessarily be horizontal, as is the case with a typical ellipsoidal joint; it can also be vertical (knee joint). If the condyles are located in different articular capsules, then such a condylar joint is close in function to the ellipsoidal joint (atlanto-occipital joint). If the condyles are close together and are located in the same capsule, as, for example, in the knee joint, then the articular head as a whole resembles a recumbent cylinder (block), dissected in the middle (the space between the condyles). In this case, the condylar joint will be closer in function to the trochlear joint.

Saddle joint, art. selldris(example - carpometacarpal joint of the first finger). This joint is formed by 2 saddle-shaped articular surfaces, sitting “astride” each other, one of which moves along and across the other. Thanks to this, movements are made in it around two mutually perpendicular axes: frontal (flexion and extension) and sagittal (abduction and adduction). In biaxial joints, a transition of movement from one axis to another is also possible, i.e., circular movement (circumductio).

Multi-axis joints.

Globular. Ball and socket joint, art. spheroidea (example - shoulder joint). One of the articular surfaces forms a convex, spherical head, the other - a correspondingly concave articular cavity.

Theoretically, the movement can occur around many axes corresponding to the radii of the ball, but practically among them three main axes are usually distinguished, perpendicular to each other and intersecting in the center of the head:

  1. transverse (frontal), around which flexion occurs, flexio, when the moving part forms an angle with the frontal plane, open anteriorly, and extension, extensio, when the angle is open posteriorly;
  2. anteroposterior (sagittal), around which abduction, abductio, and adduction, adductio, occur;
  3. vertical, around which rotation occurs, rotatio, inward, pronatio, and outward, supinatio.

When moving from one axis to another, a circular motion, circumductio, is obtained. The ball and socket joint is the loosest of all joints. Since the amount of movement depends on the difference in the areas of the articular surfaces, the articular fossa in such a joint is small compared to the size of the head. Typical ball and socket joints have few auxiliary ligaments, which determines their freedom of movement.

A type of spherical joint - cup joint, art. cotylica (cotyle, Greek - bowl). Its articular cavity is deep and covers most of the head. As a result, movement in such a joint is less free than in a typical ball-and-socket joint; We have an example of a cup-shaped joint in the hip joint, where such a device contributes to greater stability of the joint.

Flat joints, art. plana(example - artt. intervertebrales), have almost flat articular surfaces. They can be considered as the surfaces of a ball with a very large radius, so movements in them are made around all three axes, but the range of movements due to the slight difference in the areas of the articular surfaces is small. Ligaments in multiaxial joints are located on all sides of the joint.

Stiff joints - amphiarthrosis. Under this name there is a group of joints with different shapes of articular surfaces, but similar in other ways: they have a short, tightly stretched articular capsule and a very strong, non-stretchable auxiliary apparatus, in particular short reinforcing ligaments (for example, the sacroiliac joint). As a result, the articular surfaces are in close contact with each other, which sharply limits movement. Such inactive joints are called tight joints - amphiarthrosis (BNA). Tight joints soften shocks and shocks between bones. These joints also include flat joints, art. plana, in which, as noted, the flat articular surfaces are equal in area. In tight joints, movements are sliding and extremely insignificant.

Section Description

Human joints are movable connections between two or more bones. It is thanks to them that a person can move and perform various actions. They join the bones together to form the skeleton. Almost all joints have the same anatomy, they differ only in shape and movements performed.

How many joints does a person have?

A person has over 180 joints. There are these types of joints, depending on the part of the body:

  • temporomandibular;
  • connections of the hand and foot;
  • carpal;
  • elbows;
  • axillary;
  • vertebrates;
  • chest;
  • hip;
  • sacral;
  • knee

The table shows the number of joints depending on the part of the body.

Classification is carried out according to the following criteria:

  • form;
  • number of articular surfaces;
  • functions.

According to the number of articular surfaces, there are simple, complex, complex and combined. The first are formed from the surfaces of two bones, an example is the interphalangeal joint. Complex joints are connections of three or more articular surfaces, for example, ulnar, humeral, radial.

Unlike a complex joint, a combined joint differs in that it consists of several separate joints that perform one function. An example would be radioulnar or temporomandibular.

Complex is two-chambered because it has intra-articular cartilage that divides it into two chambers. This is what the knee is like.

The shape of the joint is as follows:

  • Cylindrical. Outwardly they look like a cylinder. An example is the radioulnar.
  • Block-shaped. The head looks like a cylinder, with a ridge at the bottom located at an angle of 90˚. There is a depression under it in another bone. An example is the ankle.
  • Helical. This is a type of block-shaped. The difference is the spiral arrangement of the groove. This is the shoulder-elbow joint.
  • Condylar. These are the knee and temporomandibular joints. The articular head is located on a bony protrusion.
  • Ellipsoidal. The articular head and socket are ovoid in shape. An example is the metacarpophalangeal joint.
  • Saddle-shaped. The articular surfaces are saddle-shaped, they are located perpendicular to each other. The carpometacarpal joint of the thumb is saddle-shaped.
  • Globular. The articular head is in the form of a ball, the cavity is a notch that is suitable in size. An example of this type is the shoulder.
  • Cup-shaped. This is a type of spherical. Movement is possible in all three axes. This is the hip joint.
  • Flat. These are joints with a small range of motion. This type includes articulations between vertebrae.

There are also varieties depending on mobility. There are synarthrosis (fixed articular joints), amphiarthrosis (partially mobile) and diarthrosis (mobile). Most bone joints in humans are movable.

Structure

Anatomically, the joints are built the same way. Main elements:

  • Articular surface. The joints are covered with hyaline cartilage, less often fibrous. Its thickness is 0.2-0.5 mm. This coating facilitates sliding, softens impacts and protects the capsule from destruction. When the cartilage covering is damaged, joint diseases appear.
  • Joint capsule. It surrounds the joint cavity. Consists of an outer fibrous and inner synovial membrane. The function of the latter is to reduce friction due to the release of synovial fluid. When the capsule is damaged, air enters the joint cavity, which leads to divergence of the joint surface.
  • Joint cavity. This is a closed space that is surrounded by a cartilaginous surface and a synovial membrane. It is filled with synovial fluid, which also serves as a moisturizer.

Auxiliary elements are intra-articular cartilage, discs, lips, menisci, intracapsular ligaments.

Tendons and ligaments strengthen the capsule and promote joint movement.

The most important large joints in humans are the shoulder, hip and knee. They have a complex structure.

The shoulder is the most mobile; movements around three axes are possible in it. It is formed by the head of the humerus and the glenoid cavity of the scapula. Thanks to its spherical shape, the following movements are possible:

  • raising of hands;
  • lead upper limbs back;
  • rotation of the shoulder together with the forearm;
  • movement of the brush in and out.

The hip is subjected to heavy loads; it is one of the most powerful. Formed by the acetabulum of the pelvic bone and the head of the femur. Like the shoulder, the hip has a spherical shape. Movements around three axes are also possible.

The most complex structure is at the knee joint. It is formed by the femoral, tibial and fibula, plays big role in movement, since rotation occurs along two axes. Its shape is condylar.

The knee includes many auxiliary elements:

  • external and internal meniscus;
  • synovial folds;
  • intra-articular ligaments;
  • synovial bursae.

Menisci act as shock absorbers.

Functions

All joints play an important role, without them a person would not be able to move. They connect bones, ensure their smooth sliding, and reduce friction. Without them, the bones will collapse.

In addition, they maintain the position of the human body, participate in the movement and movement of body parts relative to each other.

The functions of human joints are determined by the number of axes. Each axis has inherent movements:

  • around the transverse there is flexion and extension;
  • around the sagittal – approaching and moving away;
  • around the vertical – rotation.

Several types of movement can occur at one joint joint.

Circular rotations are possible when moving around all axes.

Depending on the number of axes, there are the following types of articular joints:

  • uniaxial;
  • biaxial;
  • multi-axis.

The table shows possible joint shapes according to the number of axes.

Joints are susceptible to disease. A change in their shape leads to disruption of the functioning of the entire musculoskeletal system.

It is very important to seek medical help promptly. There should be cause for concern painful sensations. Without joints, the human skeleton would not exist, so it is necessary to maintain their normal functioning.

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The human skeleton consists of more than 200 bones, most of which are movably connected by joints and ligaments. It is thanks to them that a person can move freely and perform various manipulations. In general, all joints are structured the same. They differ only in shape, nature of movement and the number of articulating bones.

Joints simple and complex

Classification of joints by anatomical structure

According to their anatomical structure, joints are divided into:

  1. Simple. The joint consists of two bones. An example is the shoulder or interphalangeal joints.
  2. Complex. A joint is formed by 3 or more bones. An example is the elbow joint.
  3. Combined. Physiologically, the two joints exist separately, but function only in pairs. This is how the temporomandibular joints are designed (it is impossible to lower only the left or right side jaws, both joints work simultaneously). Another example is symmetrically located facet joints spinal column. The structure of the human spine is such that movement in one of them entails displacement of the other. To understand more precisely the principle of operation, read the article with beautiful illustrations about the Structure of the human spine.
  4. Complex. The joint space is divided into two cavities by cartilage or meniscus. An example is the knee joint.

Classification of joints by shape

The shape of the joint can be:

  1. Cylindrical. One of the articular surfaces looks like a cylinder. The other has a recess of suitable size. The radioulnar joint is a cylindrical joint.
  2. Block-shaped. The head of the joint is the same cylinder, on the lower side of which a ridge is placed perpendicular to the axis. On the other bone there is a depression - a groove. The comb fits the groove like a key to a lock. This is how the ankle joints are designed.
    A special case of trochlear joints is the helical joint. His distinctive feature consists in a spiral arrangement of the groove. An example is the shoulder-elbow joint.
  3. Ellipsoidal. One articular surface has an ovoid convexity, the second has an oval notch. These are the metacarpophalangeal joints. When the metacarpal sockets rotate relative to the phalangeal bones, complete bodies of rotation are formed - ellipses.
  4. Condylekov. Its structure is similar to the ellipsoidal one, but its articular head is located on a bony protrusion - the condyle. An example is the knee joint.

  5. Saddle-shaped. In its form, the joint is similar to two nested saddles, the axes of which intersect at right angles. The saddle joint includes the carpometacarpal joint of the thumb, which among all mammals is present only in humans.
  6. Globular. The joint articulates the ball-shaped head of one bone and the cup-shaped notch of another. A representative of this type of joint is the hip. When the socket of the pelvic bone rotates relative to the femoral head, a ball is formed.
  7. Flat. The articular surfaces of the joint are flattened, the range of motion is insignificant. The flat one includes the lateral atlantoaxial joint, connecting the 1st and 2nd cervical vertebrae, or lumbosacral joints.
    A change in the shape of the joint leads to dysfunction of the musculoskeletal system and the development of pathologies. For example, against the background of osteochondrosis, the articular surfaces of the vertebrae shift relative to each other. This condition is called spondyloarthrosis. Over time, the deformity becomes fixed and develops into a permanent curvature of the spine. Helps detect the disease instrumental methods examinations (computed tomography, radiography, MRI of the spine).

Division by nature of movement

The movement of bones in a joint can occur around three axes - sagittal, vertical and transverse. They are all mutually perpendicular. The sagittal axis is located in the front-to-back direction, the vertical axis is from top to bottom, the transverse axis is parallel to the arms extended to the sides.
Based on the number of axes of rotation, joints are divided into:

  • uniaxial (these include block-shaped),
  • biaxial (ellipsoidal, condylar and saddle-shaped),
  • multi-axial (spherical and flat).

Summary table of joint movements

Number of axes Joint shape Examples

One Cylindrical Median Antlantoaxial (located between the 1st and 2nd cervical vertebrae)

One trochlear ulna

Two Ellipsoid Atlanto-occipital (connects the base of the skull with the upper cervical vertebra)

Two Condylar Knee

Two Saddle Carpometacarpal Thumb

Three Ball Shoulder

Three Flat Facet Joints (included in all parts of the spine)


Classification of types of movements in joints:

Movement around the frontal (horizontal) axis - flexion (flexio), i.e. decreasing the angle between the articulating bones, and extension (extensio), i.e. increasing this angle.
Movements around the sagittal (horizontal) axis - adduction (adductio), i.e. approaching the median plane, and abduction (abductio), i.e. moving away from it.
Movements around the vertical axis, i.e. rotation (rotatio): inward (pronatio) and outward (supinatio).
Circular movement (circumductio), in which a transition is made from one axis to another, with one end of the bone describing a circle, and the entire bone - the figure of a cone.

An introductory list of the most common diseases:

osteo911.ru

Structure

In the structure of any articular joint, the main articular components are distinguished: the articular surface of the epiphysis of the bone, synovial fluid, synovial cavity, synovial membrane, and compound bursa. In addition, the structure of the knee contains a meniscus (it is a cartilaginous formation that optimizes the alignment of the articular surfaces and acts as a shock absorber).

The articular surface of any bone is covered with hyaline cartilage, sometimes fibrous. The thickness of hyaline cartilage is about half a millimeter. The smoothness of hyaline cartilage is ensured by constant friction. Cartilage has elastic properties and therefore performs a buffer function.

The joint capsule, or capsule, is attached to the bones near the edges of the articular surfaces. Its function is to protect against damage (usually ruptures and mechanical damage), in addition, the internal synovial membrane performs the function of secreting synovial fluid. The outside of the bag is covered with a fibrous membrane, and the inside is lined with a synovial membrane. The outer layer is stronger and thicker than the inner one, the fibers are directed longitudinally.


As for the synovial cavity, it is a closed, sealed, slit-shaped space that is bounded by the articular surfaces of the bones and the synovial membrane. If we look at the knee, then in the synovial cavity there is a meniscus.

Additional articular components are muscles and tendons, ligaments, nerves and vessels that directly surround the joint, provide its nutrition and innervation. They are also called joint tissues. These tissues provide mobility and perform a strengthening function. It is through them that the vessels pass microvasculature, which nourish the joint, and thin “branches” of nerves that directly innervate it.

Currently, all joints are classified by the number of surfaces, by function and by the shape of the articular surface.

1. By number of surfaces:

1.1. Simple joint. It consists of two surfaces. An example is the interphalangeal joint.

1.2. Difficult. It consists of three or more surfaces. An example is the elbow joint.

1.3. Complex. It consists of cartilage, which divides the joint into two chambers. An example is the temporomandibular joint.

1.4. Combined. It consists of several isolated joints. An example is the temporomandibular joint.

2. According to their function and form, they are divided into:

2.1. With one axis.

2.1.1. In the form of a cylinder. An example is the atlantoaxial joint of the spine.

2.1.2. Blocky (block-shaped). An example is the interphalangeal joints.

2.1.3. In the form of a screw. An example is the shoulder-elbow joint.

2.2. With two axes.

2.2.1. In the form of an ellipse. An example is the wrist joint.

2.2.2. Condylar. An example of such a joint is the knee.

2.2.3. In the form of a saddle. An example is the carpometacarpal joint for the first finger.

2.3. Having more than two axes.

2.3.1. In the form of a ball. An example is the shoulder.

2.3.2. In the form of a bowl. An example is the hip joint.

2.3.3. Flat. An example of this is the intervertebral joint.

Before talking about these diseases, I would like to immediately say that they are a serious pathology. It should only be treated qualified specialists! Self-medication in in this case is strictly contraindicated, because it can only aggravate the course of an already severe and slow-onset disease.

Regarding joint diseases, then quite a lot of them have now been allocated. Below are the most common ones.

Some diseases

Hypermobility

Increased mobility, or - the second name - hypermobility of the joint, is characterized by congenital sprain of the ligaments, which makes it possible to perform movements that go beyond the average limits. As a result of such movement, you can hear a characteristic click (it should be noted right away that this click can be a symptom of other conditions, for example, excessive salt deposition due to metabolic disorders).


The cause of excessive ligament extensibility is disturbances in the structure of collagen fibers, as a result, the strength of collagen decreases, and, accordingly, it becomes more elastic and more susceptible to stretching. Scientists have established the hereditary nature of the transmission of this condition, but the mechanism of development is not fully understood.

Increased mobility is detected most often in young women.

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Anatomical features

Human joints are the basis of every body movement. They are found in all bones of the body (the only exception is hyoid bone). Their structure resembles a hinge, due to which the bones slide smoothly, preventing their friction and destruction. A joint is a movable connection of several bones, and in the body there are more than 180 of them in all parts of the body. They are immobile, partially movable, and the main part is represented by movable joints.

The degree of mobility depends on the following conditions:

  • volume of connecting material;
  • type of material inside the bag;
  • shapes of bones at the point of contact;
  • the level of muscle tension, as well as ligaments inside the joint;
  • their location in the bag.

How is the joint structured? It looks like a bag of two layers that surrounds the junction of several bones. The bursa ensures the tightness of the cavity and promotes the production of synovial fluid. It, in turn, acts as a shock absorber for bone movements. Together they perform three main functions of the joints: they help stabilize the body position, are part of the process of movement in space, and ensure the movement of parts of the body in relation to each other.

Basic elements of a joint

The structure of human joints is complex and is divided into the following basic elements: cavity, capsule, surface, synovial fluid, cartilage, ligaments and muscles. We'll talk briefly about each below.

  • The joint cavity is a slit-like space, which is hermetically sealed and filled with synovial fluid.
  • Joint capsule - consists of connective tissue that envelops the connecting ends of the bones. The capsule is formed on the outside from a fibrous membrane, but inside it has a thin synovial membrane (a source of synovial fluid).
  • Articular surfaces have special form, one of them is convex (also called the head), and the second is pit-shaped.

  • Synovial fluid. Its main function is to lubricate and moisturize surfaces; it also plays an important role in fluid exchange. It is a buffer zone during various movements (pushing, jerking, squeezing). Provides both sliding and divergence of bones in the cavity. A reduction in the amount of synovium leads to a number of diseases, bone deformations, loss of a person’s ability to perform normal physical activities and, as a result, even disability.
  • Cartilage tissue (thickness 0.2 - 0.5 mm). The surfaces of the bones are covered with cartilage tissue, the main function of which is shock absorption during walking and sports. The anatomy of cartilage is represented by connective tissue fibers that are filled with fluid. This, in turn, nourishes the cartilage when it is at rest, and during movement it releases fluid to lubricate the bones.
  • Ligaments and muscles are auxiliary parts of the structure, but without them the normal functionality of the entire body is impossible. With the help of ligaments, bones are fixed without interfering with movements of any amplitude due to their elasticity.

The inert protrusions around the joints also play an important role. Their main function- limitation of range of motion. As an example, consider the shoulder. There is a bony tubercle in the humerus. Due to its location next to the process of the scapula, it reduces the range of motion of the arm.

Classification and types

In development human body, way of life, mechanisms of interaction between a person and the external environment, the need to perform various physical actions, and various types of joints were obtained. The classification of joints and its basic principles are divided into three groups: the number of surfaces, the shape of the end of the bones, and functionality. We'll talk about them a little later.

The main type in the human body is the synovial joint. Its main feature is the connection of bones in the bag. This type includes shoulder, knee, hip and others. There is also a so-called facet joint. Its main characteristic is the limitation of rotation to 5 degrees and tilt to 12 degrees. The function also consists of limiting the mobility of the spine, which helps maintain the balance of the human body.

By structure

In this group, the classification of joints occurs depending on the number of bones that connect:

  • A simple joint is a connection between two bones (interphalangeal bones).
  • Complex – a connection of more than two bones (elbow). The characteristics of such a connection imply the presence of several simple bones, while the functions can be implemented separately from each other.
  • Complex joint - or two-chamber, which contains cartilage connecting several simple joints ( lower jaw, radioulnar). Cartilage can separate the joints either completely (disc shape) or partially (meniscus in the knee).
  • Combined - combines isolated joints that are placed independently of each other.

According to the shape of the surfaces

The shapes of the joints and the ends of the bones have the shape of various geometric shapes (cylinder, ellipse, ball). Depending on this, movements are carried out around one, two, or three axes. There is also a direct relationship between the type of rotation and the shape of the surfaces. Next, detailed classification joints according to the shape of its surfaces:

  • Cylindrical joint - the surface has the shape of a cylinder, rotates around one vertical axis (parallel to the axis of the connected bones and the vertical axis of the body). This species may have a rotational name.
  • Block joint - a cylinder-shaped joint (transverse), one axis of rotation, but in the frontal plane, perpendicular to the connected bones. Characteristic movements are flexion and extension.
  • Helical is a variation of the previous type, but the axes of rotation of this form are located at an angle other than 90 degrees, forming helical rotations.
  • Ellipsoidal - the ends of the bones have the shape of an ellipse, one of them is oval, convex, the second is concave. Movements occur in the direction of two axes: bend-unbend, abduct-adduct. The ligaments are perpendicular to the axes of rotation.
  • Condylar is a type of ellipsoidal. The main characteristic is the condyle (a rounded process on one of the bones), the second bone is in the form of a depression, and can differ significantly in size from each other. The main axis of rotation is represented by the frontal one. The main difference from the block-shaped one is the strong difference in the size of the surfaces, from the ellipsoidal one - the number of heads of connecting bones. This type has two condyles, which can be located either in the same capsule (similar to a cylinder, similar in function to the trochlear one) or in different capsules (similar to the ellipsoidal one).

  • Saddle-shaped - formed by connecting two surfaces as if “sitting” on each other. One bone moves lengthwise, while the second moves across. Anatomy involves rotation around perpendicular axes: flexion-extension and abduction-adduction.
  • Ball-and-socket joint - the surfaces are shaped like balls (one convex, the other concave), due to which people can make circular movements. Basically, rotation occurs along three perpendicular axes, the intersection point being the center of the head. The peculiarity is a very small number of ligaments, which does not interfere with circular rotations.
  • Cup-shaped - the anatomical appearance suggests deep depression one bone that covers most of the area of ​​the head of the second surface. As a result, there is less free mobility compared to the spherical one. Necessary for greater joint stability.
  • Flat joint - flat ends of bones of approximately the same size, interaction along three axes, the main characteristic is a small range of motion and surrounded by ligaments.
  • Tight (amphiarthrosis) - consists of bones of different sizes and shapes that are closely connected to each other. Anatomy: inactive, surfaces are represented by tight capsules, non-elastic short ligaments.

By nature of movement

Due to their physiological characteristics, joints perform many movements along their axes. In total, there are three types in this group:

  • Uniaxial - which rotate around one axis.
  • Biaxial - rotation around two axes.
  • Multi-axis - mainly around three axes.
Axis classification Species Examples
Uniaxial Cylindrical Atlanto-axial median
Block-shaped Interphalangeal joints fingers
Helical Humeral-ulnar
Biaxial Ellipsoidal Radiocarpal
Condylar Knee
Saddle Carpometacarpal joint of the thumb
Multi-axis Globular Brachial
Cup-shaped Hip
Flat Intervertebral discs
Tight Sacroiliac

In addition, there are also different types joint movements:

  • Flexion and extension.
  • Rotation in and out.
  • Abduction and adduction.
  • Circular movements (surfaces move between axes, the end of the bone draws a circle, and the entire surface draws the shape of a cone).
  • Sliding movements.
  • Removal from one another (for example, peripheral joints, distance of fingers).

The degree of mobility depends on the difference in the size of the surfaces: the larger the area of ​​one bone over another, the greater the range of movement. Ligaments and muscles can also inhibit range of motion. Their presence in each type is determined by the need to increase or decrease the range of motion of a certain part of the body.

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Shoulder joint

It is the most mobile in humans and is formed by the head of the humerus and the articular cavity of the scapula.

The articular surface of the scapula is surrounded by a ring of fibrocartilage - the so-called articular lip. The tendon of the long head of the biceps brachii muscle passes through the joint cavity. The shoulder joint is strengthened by the powerful coracohumeral ligament and surrounding muscles - deltoid, subscapularis, supra- and infraspinatus, teres major and minor. The pectoralis major and latissimus dorsi muscles also take part in shoulder movements.

The synovial membrane of the thin joint capsule forms 2 extra-articular inversions - the tendons of the biceps brachii and subscapularis. The blood supply to this joint includes the anterior and posterior arteries, which bend around the humerus, and the thoracoacromial artery; venous outflow is carried out into the axillary vein. The outflow of lymph occurs in the lymph nodes of the axillary region. The shoulder joint is innervated by branches of the axillary nerve.

The shoulder joint is capable of movement around 3 axes. Flexion is limited by the acromion and coracoid processes of the scapula, as well as the coracobrachial ligament, extension by the acromion, coracobrachial ligament and joint capsule. Abduction in the joint is possible up to 90°, and with the participation of the upper limb belt (when the sternoclavicular joint is included) - up to 180°. Abduction stops when the greater tuberosity of the humerus rests on the coracoacromial ligament. The spherical shape of the articular surface allows a person to raise his arm, move it back, and rotate the shoulder together with the forearm and hand in and out. This variety of hand movements was a decisive step in the process of human evolution. The shoulder girdle and shoulder joint in most cases function as a single functional formation.

Hip joint

It is the most powerful and heavily loaded joint in the human body and is formed by the acetabulum of the pelvic bone and the head of the femur. Hip joint strengthened by the intra-articular ligament of the femoral head, and also transverse ligament acetabulum, which surrounds the neck of the femur. From the outside, the powerful iliofemoral, pubofemoral and ischiofemoral ligaments are woven into the capsule.

The blood supply to this joint is through the circumflex femoral arteries, branches of the obturator and (variably) branches of the superior perforating, gluteal and internal pudendal arteries. The outflow of blood occurs through the veins surrounding the femur into the femoral vein and through the obturator veins into the iliac vein. Lymphatic drainage occurs in the lymph nodes located around the external and internal iliac vessels. The hip joint is innervated by the femoral, obturator, sciatic, superior and inferior gluteal and pudendal nerves.
The hip joint is a type of ball-and-socket joint. It allows movements around the frontal axis (flexion and extension), around the sagittal axis (abduction and adduction) and around the vertical axis (external and internal rotation).

This joint experiences a lot of stress, so it is not surprising that its lesions occupy first place in the general pathology of the articular apparatus.

Knee joint

One of the largest and most complex human joints. It is formed by 3 bones: the femur, tibia and fibula. Stability of the knee joint is provided by intra- and extra-articular ligaments. The extra-articular ligaments of the joint are the fibular and tibial collateral ligaments, the oblique and arcuate popliteal ligaments, the patellar ligament, and the medial and lateral suspensory ligaments of the patella. The intra-articular ligaments include the anterior and posterior cruciate ligaments.

The joint has many auxiliary elements, such as menisci, intra-articular ligaments, synovial folds, and bursae. Each knee joint has 2 menisci - the outer and the inner. The menisci look like crescents and play a shock-absorbing role. TO auxiliary elements This joint includes synovial folds, which are formed by the synovial membrane of the capsule. Knee joint also has several synovial bursae, some of which communicate with the joint cavity.

Everyone had to admire the performances of artistic gymnasts and circus performers. People who are able to climb into small boxes and bend unnaturally are said to have gutta-percha joints. Of course, this is not true. The authors of The Oxford Handbook of Body Organs assure readers that “their joints are phenomenally flexible”—medically known as joint hypermobility syndrome.

The shape of the joint is a condylar joint. It allows movements around 2 axes: frontal and vertical (with a bent position in the joint). Flexion and extension occur around the frontal axis, and rotation occurs around the vertical axis.

The knee joint is very important for human movement. With each step, by bending, it allows the foot to step forward without hitting the ground. Otherwise, the leg would be carried forward by raising the hip.

According to the World Health Organization, every 7th person on the planet suffers from joint pain. Between the ages of 40 and 70 years, joint diseases are observed in 50% of people and in 90% of people over 70 years of age.
Based on materials from www.rusmedserver.ru, meddoc.com.ua

See also:

7 Early Signs of Arthritis

8 Ways to Destroy Your Knees

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Simple and complex joints

The simple joint got its name, as you might guess, because of the simplicity of its design. The main elements of the joint form the surfaces of two bones. To make it easier to understand where it is, just look at the person’s shoulder. The humerus and the socket of the scapula are connected by a special tissue. Complex design will consist of 3 simpler designs that are united by a common capsule. For example, the elbow joint is complex because it has the surfaces of three bones:

  • brachial;
  • elbow;
  • ray.

Non-specialists in medicine often confuse combined joints with complex joints, which is quite natural, since these elements are similar to each other. Only the complex one in its design has a common capsule, while the combined one does not have it. The second joint differs from the previous ones in that its components are separated, but this does not prevent them from functioning together. The right and left temporomandibular joints are classified as combined. A complex joint, in turn, is similar to a combined joint. Sometimes you can find information in publications that they are considered as a single group, which is incorrect, since these are different elements. Characteristic complex joint differs from the combined one and indicates that the former consists of intra-articular cartilage. The last element divides it into two chambers, but the combined joint does not have them.

Geometry plays a special role in anatomy, because many parts of the body get their names due to their similarity to one or another geometric figure. When dividing various forms of human joints into groups, associations of similarity of body elements with geometric shapes. For example, from the name “ball and socket joint” you can already get an idea of ​​its shape. This element is capable of moving in a circle and is considered the most free. The ball and socket joint is characterized by increased mobility, thanks to which a person can carry out circular movements.

The spherical nature of this design allows people to rotate, bend and move their limbs along complex trajectories.

Cylindrical, helical, flat joints

A human joint can also have a cylindrical shape. This fastening group is also capable of ensuring rotational movements of body parts. The cylindrical joint is located in the first and second cervical vertebrae, it is present where the heads radius and the ulna are connected to each other. The cylindrical joint belongs to the category of structures with one axis of movement; if it is damaged, the mobility of the cervical vertebrae is impaired. The trochlear joint looks like a cylinder and belongs to the category of structures with one axis of movement. It is more durable and is located in the ankle. The interphalangeal joints are also block-shaped.

A helical joint is often called a trochlear joint, which is quite natural, since the first is a variation of the second. Both have the same axis of movement. But in a helical one, the guide roller and the recess form a helical direction on its cylindrical surface. The trochlear joint does not have this property. As for helical analogues, the elbow belongs specifically to this category of elements of the human body. U flat designs the structure is much simpler than that of the helical ones, but the former are no less important in the functioning of the body.

The flat design sits on the wrist. It is distinguished by its simplest form and small number of movements. It is called “flat” because it consists of flat bone surfaces, whose movement is limited by ligaments and bony processes.

One flat joint does not have a significant range of motion, but if a whole group of such elements is involved in the process, the situation changes. Together they are able to carry out complex work, and the range of tasks they perform increases significantly.

Different surfaces and configurations

The names of joints have the property of indicating what parts the biomechanical elements of the body consist of. Joints are discontinuous connections of bones that contain cartilage-covered surfaces and capsules.

They have cavities where synovial fluid is located, a thick, elastic mass that washes it. There are not only different forms, but also elements of such structures. Their disks may be present in some designs, but not in others. There are varieties that have menisci and special lips. Their surfaces can be different in configuration, their shapes may or may not correspond to each other. But at the same time, without synovial fluid, their tissues are not able to carry out their activities, and their basic elements remain the same.

When it comes to the synovial joint, a discussion of the treatment of musculoskeletal diseases often begins. Its peculiarity is the bag, where the ends of the bones are located. Synovial fluid is found in this sac. Most forms of such structures in the human body are synovial. It is the synovial fluid that prevents the joints from wearing out when they move along the axis of rotation. If the synovial fluid stops being renewed in the human body, this means: the pressure in the joint will increase, and it, moving along the axis of rotation, will begin to wear out, like cartilage.

When do they arise? destructive changes in joint tissue (and they usually develop against the background of impaired metabolism), they are followed by various types of their diseases.

Functions performed by joints

There is an anatomical classification of joints depending on the sections. Not only the characteristics of the constituent parts of each element are taken into account, but also their location on the human body and the functions performed. There are the following types of joints:

  • movable joints of the ends of the bones of the hand and foot;
  • elbows;
  • axillary;
  • vertebrates;
  • carpal;
  • hip;
  • sternoclavicular;
  • sacroiliac;
  • temporomandibular;
  • knee

The anatomical table provides a more complete classification of them (Fig. 1, 2). The functioning of joint tissue is directly affected by the elements it connects. For example, intervertebral joints have limited movement because the spinal discs are located between them. The subtalar joint is located between the talus and calcaneus bones. Its exact location is their posterior section. It is considered one of the areas of the body that are significantly susceptible to dislocation. In terms of the number of dislocations, this element is in 3rd place after dislocations that affect the Lisfranc joint. It is located transversely.

The last of them is the tarsometatarsal, which, located in the middle part of the foot, has specific features anatomical structure. The Lisfranc joint does not have a ligament between the bases of the first and second metatarsal bones; it belongs to the category of tarsometatarsal analogues and crosses the foot in its middle part. The Lifranc joint belongs to the category of flat analogues and is the most vulnerable point of the body for the occurrence of fractures and dislocations.

To strengthen the Lifranc joint, modern medicine actively uses techniques manual therapy. Nearby, in the area of ​​the foot, is the Chopart joint. It is considered more durable, this property is due to the peculiarities of its anatomical structure. In a cross section, Chopara (tarsal-transverse) resembles the shape of the letter S.

In the foot area it is strengthened by ligaments, which significantly reduces the level of trauma in this area. It also differs in that it has a common ligament.

Mysteries and discoveries of human anatomy

The heel joint is located in the foot area, unique in that it connects three types of bones. It unites not only the calcaneus and navicular bones, but also the one located in the talus. It is a single whole with other tissues located around it. The bone located at the talus is one of those that form lower section ankle joint. As a legacy from the world of mammals, humans have inherited a large number of joints of the lower extremities, in which there are many joints of various bones that provide mobility and make it possible to move in space. The hock joint is common to horses, cats, dogs and other species of animals. Many people believe that people have it. However, in humans it is absent, but in the course of evolution, people have developed its replacement - the heel analogue. The latter has a similar set of functions to the hock joint and is closely related to the functioning of the human musculoskeletal system. It's quite complex. It includes 6 bones with different shape and size.

The fetlock joint is also characteristic of the world of mammals. Visually, its damage becomes noticeable when the animal begins to limp. In horses, the fetlock joint is most often affected by arthritis, a disease that is also common in humans. In the process of man's transition to upright posture, his musculoskeletal system and tissues have changed significantly, and the fetlock joint is absent in the human body today. It is noteworthy that traditional medicine prefers to treat a number of diseases using extracts from animal bones. Beef fetlock is no exception. It contains vitamins and microelements necessary for the restoration of human tissue. It is used to prepare broths, which are recommended for people suffering from fracture-dislocations. The fetlock joint is widely used in the manufacture of medicines.

Peripheral joints were inherited by humans as a legacy of the animal world. They are no less important than the central joints. Elderly people most often suffer from damage to peripheral joints by various arthritis, which significantly worsens their quality of life. The facet joints are most often called intervertebral joints, this group helps the spine to be flexible and mobile. This model is also present in animals. In them, like in humans, it has a relatively wide articular capsule. If it is disturbed, a person begins to experience pain in the spine. Painful symptoms include the neck, chest, lumbar regions. The facet joint gets its name from the unusual shape of its processes. No less interesting is their location in the body - on both sides of the spinal column. The facet, also called the facet, makes the spine so flexible and mobile. Various movements occur between its vertebrae.

Treatment of diseases

The occipital joint is responsible for connecting the skull to the spine. Modern medicine this category defined as the atlanto-occipital and atlanto-axial joints. The presence of such joints is a feature of the structure of the human body, but they have their own specifics. Like them, the occipital joint belongs to the category of paired joints; it connects bone tissues of different densities. Even at the dawn of studying the structure of the human body, it was found out that the occipital joint has an ellipsoidal shape. Thanks to it, a person can tilt their head forward. If the occipital component is damaged, head movements become limited. Such structures are vulnerable, and in the event of injury to the back of the head, it is often necessary to surgery to restore the occipital component. Titanium plates are also used for this.

In order to treat such diseases and restore damage to their tissues, humanity uses various achievements of scientific and technological progress. Titanium alloy does not cause rejection by the human body, which makes it possible to perform joint replacement. The titanium element is practically no different from the natural one, but it is more durable and will allow you to maintain joint mobility in cases where tissue destruction occurs.

The titanium alloy from which joints are made is today the only chance for many people to avoid disability.