Diagram of the structure of a simple and complex joint of animals. The structure of the joint. Types of joints by structure, movement

CLASSIFICATION OF JOINTS AND THEIR GENERAL CHARACTERISTICS

The classification of joints can be carried out according to the following principles: 1) by the number of articular surfaces, 2) by the shape of the articular surfaces and 3) by function.

According to the number of articular surfaces, there are:

1. Simple joint(art. simplex), which has only 2 articular surfaces, such as interphalangeal joints.

2. Complex joint(art. composita), which has more than two articular surfaces, such as the elbow joint. A complex joint consists of several simple joints in which movements can be performed separately. The presence of several joints in a complex joint determines the commonality of their ligaments.

3. Complex joint(art. complexa), containing intra-articular cartilage inside the articular bag, which divides the joint into two chambers (two-chamber joint). The division into chambers occurs either completely if the intra-articular cartilage is disc-shaped (eg, in the temporomandibular joint) or incompletely if the cartilage takes the form of a semilunar meniscus (eg, in the knee joint).

4. Combined joint represents a combination of several joints isolated from each other, located separately from each other, but functioning together. Such, for example, are both temporomandibular joints, the proximal and distal radioulnar joints, etc. Since the combined joint is a functional combination of two or more anatomically separate joints, this distinguishes it from the complex and complex joints, each of which, being anatomically single, composed of functionally different compounds.

According to form and function, the classification is carried out as follows.

The function of the joint is determined by the number of axes around which movements are made. The number of axes around which movements occur in a given joint depends on the shape of its articular surfaces. So, for example, the cylindrical shape of the joint allows movement only around one axis of rotation. In this case, the direction of this axis will coincide with the axis of the cylinder itself: if the cylindrical head is vertical, then the movement is performed along the vertical axis (cylindrical joint); if the cylindrical head lies horizontally, then the movement will take place along one of the horizontal axes coinciding with the axis of the head, for example, the frontal (block joint).

In contrast, the spherical shape of the head makes it possible to rotate around a plurality of axes coinciding with the radii of the ball (spherical joint).

Consequently, there is a 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 articulation determines its shape.

Here we see the manifestation of the dialectical principle of the unity of form and function.

Based on this principle, we can outline the following unified anatomical and physiological classification of the joints.

Uniaxial joints. 1. Cylindrical, or wheel-shaped joint, art. trochoidea. A cylindrical or wheel-shaped articular surface, located vertically with its axis, parallel to the long axis of the articulating bones or the vertical axis of the body, provides movement along one vertical axis - rotation, rotatio; such a joint is also called rotational.

Davies distinguishes between two types of rotational joint, which he considers to be a rod joint: in the first type, the bone rod rotates in the ring formed by the glenoid cavity and the annular ligament; an example is the proximal radioulnar joint, in which the beam rotates inwards (pronation) and outwards (supination). In the second type, on the contrary, the ring formed by the ligament and the articular cavity rotates around the bone rod; an example is the articulation of the atlas with the tooth of the axial vertebra. At this joint, the ring of the atlas rotates to the right and to the left around the tooth of the axial vertebra.

2. Block joint, ginglymus (an example is the interphalangeal joints of the fingers). Its block-shaped articular surface is a transversely lying cylinder, the long axis of which lies transversely, in the 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). Guiding groove and scallop on the articulating surfaces eliminate the possibility of lateral slip and promote movement around one axis.

If the guide groove of the block is not located perpendicular to the axis of the latter, but at a certain angle to it, then when it continues, a helical line is obtained. Such a block-shaped joint is considered as a helical joint (an example is the shoulder-elbow joint). The movement in a helical joint is the same as in a purely trochlear joint.

According to the laws of the location of the ligamentous apparatus in the cylindrical joint, the guide ligaments will be located perpendicular to the vertical axis of rotation, in the 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. 1. Ellipsoid joint, articulatio ellipsoidea (an example is the 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 respectively concave. They provide movement around 2 horizontal axes perpendicular to each other: around the frontal - flexion and extension, and around the sagittal - abduction and adduction. Ligaments in ellipsoid joints are located perpendicular to the axes of rotation, at their ends.

2. Condylar joint, articulatio condylaris (an example is the 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 as a kind of ellipsoid, representing a transitional form from the block joint to the ellipsoid. Therefore, its main axis of rotation will be frontal.

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, unlike 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 in the same bag (for example, two condyles of the femur involved in the knee joint), or located in different articular capsules, as in the atlanto-occipital articulation.

Since the heads do not have the correct elliptical configuration in the condylar joint, the second axis will not necessarily be horizontal, as is typical for a typical ellipsoid 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 an ellipsoidal joint (atlanto-occipital articulation). If the condyles are close together and are 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 of the space between the condyles). In this case, the condylar joint will be closer in function to the block joint.

3. Saddle joint, art. sellaris (an example is the carpometacarpal joint of the first finger).

This joint is formed by 2 saddle-shaped articular surfaces, sitting "on top" of each other, of which one moves along and across the other. Due to this, movements are made in it around two mutually perpendicular axes: frontal (flexion and extension) and sagittal (abduction and adduction).

In biaxial joints, it is also possible to move from one axis to another, i.e., circular motion (circumductio).

Multiaxial joints. 1. Spherical. Ball joint, art. spheroidea (an example is the shoulder joint). One of the articular surfaces forms a convex spherical head, the other - a correspondingly concave articular cavity. Theoretically, movement can take place around many axes corresponding to the radii of the ball, but in practice, 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 bending forward, anteflexio, when the moving part forms with a frontal plane, an angle open anteriorly, and bending backwards, retroflexio, when the angle is open backwards; 2) anterior-posterior (sagittal), around which abduction, abductio, and adduction, adductio, are performed; 3) vertical, along the circumference of which rotation occurs, rotatio, inward and outward. When moving from one axis to another, a circular motion, circumductio, is obtained. The ball joint is the freest of all joints. Since the amount of movement depends on the difference of the articular surfaces along the length, the articular fossa in such a joint is small compared to the size of the head. There are few auxiliary ligaments in typical spherical joints, which determines the freedom of their movements.

A kind of spherical joint - cup-shaped joint, art. cotylica (cotyle, Greek - bowl). Its articular cavity is deep and covers most of the head. As a result, movements in such a joint are less free than in a typical spherical joint; we have a sample of the bowl-shaped joint in the hip joint, where such a device contributes to greater stability of the joint.

2. Flat joints, art. plana (example - artt. intervertebrals), have almost flat articular surfaces. They can be considered as the surfaces of a ball with a very large radius, therefore, movements in them are performed along all three axes, but the range of movements due to the slight difference in the articular surfaces is small.

Ligaments in multiaxial joints are located on all sides of the joint.

tight joints- amphiarthrosis. In a number of manuals, under this name, a group of joints with different forms of articular surfaces, but similar in other ways, is distinguished: they have a short, tightly stretched joint capsule and a very strong, non-stretching auxiliary apparatus, in particular, short reinforcing ligaments. As a result, the articular surfaces are in close contact with each other, which sharply limits movement. Such sedentary joints are called tight joints - amphiarthrosis. Tight joints soften shocks and tremors between bones. An example is art. mediocarpea.

These joints also include flat joints, art. plana, in which, as mentioned, the flat articular surfaces are equal in length. In tight joints, movements are of a sliding nature and are extremely insignificant.

Human joints are movable joints of two or more bones. It is thanks to them that a person can move and perform various actions. They unite the bones into a single whole, forming the skeleton. Almost all joints have the same anatomy, they differ only in shape and movements performed.

Classification and types

How many joints does a person have? There are over 180 of them. There are such types of joints, depending on the part of the body:

• temporomandibular;
• joints of the hand and foot;
• carpal;
• elbow;
• axillary;
• vertebrates;
• chest;
• hip;
• sacral;
• knee.

In the table, the number of articular connections depending on the part of the body.

Classification is carried out according to the following criteria:

• the 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 are compounds of three or more articular surfaces, for example, ulnar, humeral, radial.

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

The complex is two-chamber, because it has intra-articular cartilage, which divides it into two chambers. This is the knee.

The form of the articulation is as follows:

• Cylindrical. Outwardly, they look like a cylinder. An example is the radioulnar.
• Blocky. The head looks like a cylinder, on the bottom of which there is a comb located at an angle of 90˚. Under it there is a cavity in another bone. An example is the ankle.
• Helical. This is a type of block. The difference is the spiral arrangement of the groove. This is the shoulder joint.
• Condylar. This is the knee and temporomandibular joint. The articular head is located on the bony protrusion.
• Ellipsoid. The articular head and cavity are ovoid. An example is the metacarpophalangeal joint.
• Saddle. The articular surfaces are in the form of a saddle, they are perpendicular to each other. The carpometacarpal joint of the thumb is saddle-shaped.
• Spherical. The articular head is in the form of a ball, the cavity is a notch that is suitable in size. An example of this species 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. Articulations between vertebrae can be attributed to this type.

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

Structure

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

• articular surface. The joints are covered with hyaline cartilage, rarely fibrous. Its thickness is 0.2-0.5 mm. This coating facilitates sliding, softens impacts and protects the capsule from destruction. When the cartilage is damaged, joint diseases appear.
• articular 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 a 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 acts as a moisturizer.

Auxiliary elements are intraarticular cartilage, discs, lips, menisci, intracapsular ligaments.

Tendons and ligaments reinforce the capsule and promote movement of the joint.

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

The shoulder is the most mobile, it can move around three axes. 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 hands;
• abduction of the upper limbs back;
• rotation of the shoulder along 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 of the knee joint. It is formed by the femur, tibia and fibula, plays a large role in movement, since rotation occurs along two axes. Its shape is condylar.

The knee includes many auxiliary elements:

• outer and inner meniscus;
• synovial folds;
• intra-articular ligaments;
• synovial bags.

The menisci act as shock absorbers.

Functions

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

In addition, they support 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 motions to be performed:

• around the transverse flexion and extension occurs;
• around the sagittal - approach and removal;
• around the vertical - rotation.

In one articular joint, several types of movement can occur at once.

Circular rotations are possible when moving around all axes.

By the number of axes, there are such types of articular joints:

• uniaxial;
• biaxial;
• multiaxial.

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

Joints are prone to disease. Changing their shape leads to disruption of the functioning of the entire musculoskeletal system.

It is very important to seek medical attention in a timely manner. Pain should be a cause for concern. Without the joints, the human skeleton would not exist, so it is necessary to maintain their normal functioning.

General structure and function of the joints

The joints of our body are a true masterpiece of engineering. They combine sufficient simplicity and compact design with high strength. However, many aspects of their function are not fully understood.

There are more than 230 joints in the human body. They are represented in the skeleton wherever distinct movements of body parts occur: flexion and extension, abduction and adduction, rotation ...

The articulations of the bones a priori must be mobile so that a person can realize the motor function, and at the same time securely fastened together. The role of such "mounts" is performed by the joints.

And despite the fact that the size and shape of the joints are extremely diverse, there are mandatory elements in the design of any of them. First of all, these are two - at least - bones, because the joint is nothing but a way of connecting bones, which experts call intermittent. (There is also a continuous connection. So, for example, the bones of the skull, the bodies of the vertebrae are connected).

The discontinuous connection allows the articulating bones to move relative to each other, of course, with the help of muscles. The articular surfaces of the bones are not the same. In their shape, they can resemble a ball, ellipse, cylinder and other geometric shapes. Both articulating surfaces are “applied” with a high-strength material - cartilage, the thickness of which in different joints ranges from 0.2 to 6 millimeters.

In appearance, homogeneous, smooth and shiny cartilage under an electron microscope resembles a sponge with very thin pores. Cartilage tissue is formed by chondrocyte cells and intercellular substance, through which chondrocytes are supplied with nutrients, water, and oxygen. Observations have shown that the fibers of the intercellular substance can change their direction, adapting to long-acting loads. Such dynamism of the fibers increases the wear resistance of the cartilage tissue.

The place of articulation of the bones is surrounded by the articular capsule. The outer layer of the capsule is strong, fibrous: its inner surface is covered with a layer of endothelial cells that produce a viscous, transparent, yellowish liquid - synovia.

Synovia in the joint, as they say, the cat cried: from one to three milliliters. But its importance is difficult to overestimate. Firstly, it is an excellent lubricant: by moisturizing the articular surfaces, it reduces friction between them and thus prevents their premature wear. At the same time, the synovium strengthens the joint by creating a cohesive force between the articular surfaces. It, like a buffer, softens the shocks that the bones experience when walking, jumping, and various movements. Synovial fluid also plays an important role in providing nutrition to cartilage tissue.

It was established that each joint maintains its characteristic level of synovia. But its composition is not always the same. For example, with an increase in the speed of movement in the joint, the viscosity of the synovium decreases, due to which the friction between the articular surfaces of the bones decreases even more.

Investigating the function of the synovial membrane, scientists came to the conclusion that it works like a biological pump. The experimenters found narrowly differentiated cells of type A and B in this membrane. Type B cells specialize in the production of hyapuronic acid, which gives synovia a wonderful property to promote “frictionless movement”. Type A cells are a kind of cleaners: they suck out waste products of cell vital activity from the synovial fluid.

However, specialists know only the general scheme of the device and the operation of this living pump. Its main "knots" and features of its work have yet to be studied.

Maintaining a constant negative pressure inside the joint cavity is closely related to the function of the biological pump. This pressure is always lower than atmospheric pressure (which increases the adhesion force between the articular surfaces, they fit closer to each other), but the person does not feel it. However, we all know people whose joints become sensitive to changes in atmospheric pressure with age. But what explains this sensitivity, the researchers are not entirely clear.

The design of most joints is not limited to the required elements and includes various discs, menisci, ligaments and other "technical improvements" that nature has created in the process of evolution. In the knee joint, for example, there are two menisci: external and internal. Thanks to these sickle-shaped cartilages, rotational and flexion-extensor movements are performed in the joint, they also serve as buffers that protect the articular surfaces from sharp shocks. Their role in the physiology and mechanics of the knee joint is so great that the meniscus is sometimes called a joint in a joint.

The function assigned to the joint dictates the design. The most convincing proof of this is the joints of the hand. In the process of human labor activity, the articular and ligamentous apparatus of the hand has reached constructive perfection. A variety of combinations of joints - and there are more than twenty of them in the hand, including block-shaped ones. ellipsoid, spherical, saddle-shaped - allow differentiated movements.

Or, for example, joints such as the shoulder and hip. Both of them are spherical, both are simple, since each is made up of two bones.

Try to raise your hand through the side up. Easily! Now lift your leg. But this is much more difficult, right? Why? Yes, because in the shoulder joint, a relatively large head of the humerus corresponds to a small articular cavity of the scapula: the head is approximately three times larger than the cavity. Its capacity is increased by a fibrocartilaginous ring, the so-called articular lip, which is attached to the edge of the cavity. This structure allows you to make movements in the shoulder joint in almost all directions.

The hip joint does not have this range of motion. The main thing here is the strength of the structure: after all, the joint constantly has to experience significant both dynamic and static loads.

In this joint, the cavity of the pelvic bone almost completely covers the head of the femur, which naturally limits the range of motion. But this is not the only reason why the hip joint is less mobile than the shoulder joint. If in the shoulder joint the capsule is very spacious and slightly stretched, then in the hip joint it is less voluminous and very strong, in some places it is even reinforced with additional ligaments.

And why does it cost nothing for gymnasts, acrobats, ballet dancers, circus not only to lift their legs vertically upwards, but also to do more complex movements? This is another proof of the plasticity of the musculoskeletal system, its enormous potential.

What are the secrets of this plasticity, high performance of the joints? Experts are conducting research that will help answer this and other questions. The results of scientific research are not only of theoretical interest. Practical medicine is interested in them: surgery, orthopedics, transplantology.

Joints are the movable joints of various bones. A characteristic difference from other forms of combination of various elements in the structure of the skeleton of the human body is the presence of a certain cavity filled with liquid. Each joint consists of several parts:

• except for the connection of the lower jaw with the temporal bone) surface;
• capsule;
• cavity;
• synovial fluid.

General concept of human joints

The thickness of the cartilage layer can be different: from very thin, about 0.2 mm, to fairly thick - about 6 mm. Such a significant difference is determined by the workload on the joint. The greater the pressure and its mobility, the thicker the hyaline surface.

The classification of human joints involves dividing them into several independent groups, defined by a similar feature. It is conditionally possible to distinguish:

• by the number of surfaces - simple, complex, combined, complex;
• along the axes of rotation - uniaxial, biaxial, multiaxial;
• in shape - cylindrical, block-shaped, helical, ellipsoid, condylar, saddle-shaped, spherical, flat;
• possible movement.

Variety of combinations

The various cartilaginous surfaces that work together determine the simplicity or complexity of the joint structure. The classification of the joints (anatomy table) allows them to be divided into simple, complex, combined, complex.

Simple - characterized by the presence of two cartilaginous surfaces, and they can be formed by two or more bones. An example is the joints of the upper limb: phalangeal and radiocarpal. The first of them is formed by two bones. The second one is more complex. One of the surfaces has a base of three bones of the proximal carpal row at once.

Complex - are formed from three or more surfaces placed in one capsule. In fact, these are several simple joints that can work both together and separately. For example, the elbow joint has as many as six surfaces. They form three independent compounds in one capsule.

Some joints in their composition, in addition to the main ones, have additional devices, such as discs or menisci. The classification of joints calls them complex. The discs divide the joint cavity into two parts, thereby forming the "number of storeys" of the joint. The menisci are crescent shaped. Both devices ensure that the adjacent forms of cartilage in the joint capsule correspond to each other.

Classification of joints by structure highlights such a thing as combination. This means that two separate connections, being independent, can only work together. A typical example of such synergism is the right and left temporomandibular joints.

Possible rotation

Articular joints provide the character, amplitude and trajectory of movements of the human skeleton. Rotation occurs around biomechanical axes, which may be several. Among them are vertical, sagittal and transverse. The classification of joints on this basis distinguishes several types.

• uniaxial- have a single axis of rotation. For example, the interphalangeal joints provide flexion and extension of the fingers, other movements are impossible.
• Biaxial- two axes of rotation. A typical example is the wrist joint.
• Triaxial- movement in all possible planes - shoulder, hip joints.

Variety of forms

The classification of joints according to forms is quite extensive. Each joint has been evolutionarily adapted to reduce workload and increase manpower.

• Cylindrical. It has only one - longitudinal. Interestingly, there are cylindrical joints with a fixed center around which the ring (atlas-axis) rotates, and vice versa, as in the radioulnar joint.
• blocky- uniaxial joint. The name is directly defining its structure. One surface has the shape of a ridge, which is combined with the groove of the second cartilage, thus forming a lock (interphalangeal joints).
• helical. One of the types of block-shaped connection. It has one axis and an additional helical offset. An example is

• Ellipsoid- rotates along two axes - vertical and sagittal. Movement in this joint provides flexion, extension, adduction and abduction (wrist joint).
• Condylar. Biaxial joint. Its shape is notable for its strongly convex cartilaginous surface on one side and flatness on the other. The latter may show a slight indentation. The most striking example - Classification highlights other compounds of the condylar form. For example, the temporomandibular joint.
• saddle. Formed by two surfaces - curved and concave. The formed joint is able to move along two axes - frontal and sagittal. A striking example is the phalangeal-metacarpal joint of the thumb.

One of the most massive in the body is the hip joint. The classification calls it spherical. It has a characteristic shape. Movement is carried out along three possible axes. One of the varieties of the spherical shape is the cup-shaped joint. It is characterized by a smaller amplitude of possible movements.

The classification of bones and joints distinguishes their division into departments. For example, the belt of the lower or upper limbs, the skull, the spine. The latter consists of small bones - vertebrae. The joints between them are flat, inactive, but capable of movement along three axes.

Articular connection of the temporal bone and mandible

This joint is combined and complex. Movement occurs simultaneously on the right and left. Any axis is possible. This is provided by the adaptation of the lower jaw to chewing and talking. The joint cavity is divided in half by a cartilaginous fibrous disc, which is fused with the articular capsule.

Sore joints?

The joints in the human body perform an important function - movement. When they are healthy, the amplitude of actions is not disturbed. Life without feeling pain and discomfort is much more pleasant than with them.

There are various classification divides them into groups according to specific symptoms, the complexity of the process and the nature of the course (acute, subacute, chronic). Pathologically distinguished:

• arthralgia (joint pain of a fixed or volatile nature);
• arthritis (inflammatory processes);
• arthrosis (degenerative irreversible changes);
• congenital diseases.

Arthritis

A large number of diseases affect the supporting apparatus, causing dysfunction of the joints. The classification of arthritis distinguishes infectious, non-infectious, traumatic and concomitant (with other diseases). A detailed list was approved in 1958 at the Congress of Rheumatologists.

Infectious arthritis, which makes up an extensive group of diseases, are specific, which are caused by the damaging effect of known types of pathogens, for example, tubercle bacillus, or evolutive. Particularly distinguish diseases of the joints according to the authors: Sokolsky-Buyo, Bekhterev, Still.

Non-infectious arthritis is also called dystrophic. They occur quite often, the etiology is the most diverse. Among the reasons may be age-related changes, the negative impact of environmental factors (hypothermia, excessive stress), hormonal and metabolic disorders (gout, thyroid disease, hemophilia, etc.).

Traumatic arthritis develops with blunt trauma, joint injuries. In addition, they can occur due to prolonged exposure to vibration.

A large number of arthritis accompany other diseases that are not associated with the musculoskeletal system. Chronic forms of psoriasis, systemic lupus erythematosus, dermatoses - everything can involve the joints in the process. In addition, arthritis causes leukemia, some diseases and the nervous system. Lead intoxication also often provokes a degenerative process in the joints.

Arthralgia

Pain associated with the work of the joints is called arthralgia. The nature of its manifestation can be superficial or deep, permanent or temporary, affect one or several cartilaginous joints. The disease most often affects the largest joints in the human body: knee, elbow, hip. Smaller ones are affected much less frequently.

Arthralgias often become accompanying symptoms in various infectious diseases, especially those occurring with febrile conditions. In the diagnosis, various methods of examination are used with the obligatory collection of anamnesis. Laboratory studies involve counting the number of platelets in the blood, as well as other tests and samples.

Arthrosis

The classification of joints affected by arthrosis cannot be limited to their singularity or a specific group. In itself, this disease is quite severe, as it is associated with the destruction of cartilage. This leads to deformity of the joints. It has been proven that a significant role in the development of arthrosis is played by a genetic predisposition - heredity. At risk for this disease are people whose professions are directly related to the constant stress on the joints: hairdressers, athletes, drivers, etc. The cause may be long-term hormonal disorders in the body.

Congenital malformations of the joints

The severity of congenital malformations of the joints varies from mild to severe. There are many diseases of the newborn. These include: arthrogryposis, pseudoarthrosis of the leg, congenital dislocation of the hip or patella, hip dysplasia, (an autosomal disease).

Prevention of joint diseases

In recent years, diseases of the musculoskeletal system have become much younger. If earlier the average age of patients was at the level of 55 years, now it is fixed at the level of 40.

To avoid serious complications and live a long life without restricting your movements, it is important to monitor your general health and carry out timely prevention. It consists in controlling body weight, proper nutrition, eliminating bad habits and moderate physical activity.

The musculoskeletal system (MDA) is a very complex system responsible for the ability to move the human body in space. Structurally, it is divided into two parts - active (muscles, ligaments, tendons) and passive (bones and joints).

Interesting! The human skeleton is a kind of framework, a support for all other body systems. In an adult, it consists of 200 bones, the joints of which can be either fixed or movable.

The movable connection of the bones is provided by joints, of which there are 360. For the most part, they are located in the spine, where their number reaches 147 pieces; they provide articulation of the vertebrae with each other and with the ribs.

The main purpose of the articular connection, in addition to ensuring the mobility of the bones, is cushioning, mitigating concussions and overloads experienced by our skeleton.

All joints of our body are divided into the following main types:

Provide the most mobile connection between individual bones. They are the most complex structures and consist of several main parts. Synovial articular surfaces include the knees, shoulders, elbows, fingers, etc. Their anatomy, depending on the type, is as follows:

Fibrous

In this case, individual bones are fastened to each other with the help of cartilage. As a result, the connection is obtained, although inactive, but more durable.

In Latin, "fiber" means fiber, from which this type of connection got its name. The sternum, ribs, intervertebral discs, as well as the pelvic bones and some bones of the skull are articulated in a fibrous way.

fibrous

In this case, the bones are interconnected so rigidly that they practically form a monolithic surface. At the same time, the connective cartilage tissue hardens so much that it loses all elasticity. Large bones of the cranial vault (frontal, parietal, temporal) are articulated in a similar way.

Classification of human joints

The synovial joints of the human skeleton are divided into several types. Due to the large number of different articular joints, a "table of joints" has been developed in biology to differentiate them. In modern human anatomy, joints are classified according to several criteria:

1. By the number of surfaces.
2. The shape of the surfaces.
3. Degrees of freedom in motion.

Number of surfaces

The connection of bones can have several surfaces of the articulation, depending on what they are divided into the following types.

Simple joint (simplex)

Simple joints have only two movable articular surfaces, between which there are no additional inclusions. An example of such joints is the phalanges of the fingers, shoulder or hip joints. So, a simple connection is formed by the articular cavity of the scapula and the head of the humerus.

Complex (composite)

Such a connection has more than two articular surfaces. This type includes the elbow joint, which is more complex than the same shoulder joint. They may also have additional inclusions - cartilage or bone. Such structures are called complex and combined joints. The scheme of their structure differs from simple ones in that their design may include any additional components:

1. Complex - contain in their structure an intra-articular cartilaginous element (meniscus, or cartilaginous disc). It divides the joint from the inside into two isolated parts. An example of a complex articulation is the knee joint, in which the meniscus divides the intraarticular cavity into two halves.

1. Combined - are a combination of several joints isolated from each other, which, despite this, work as a single mechanism. An example is the temporomandibular joint, which is responsible for the mobility of the lower jaw. At the same time, thanks to a complex connection mechanism, its mobility is ensured in several directions at once: up-down, forward-backward, right-left.

The nature of the movement (degrees of freedom) of human joints

The joints of individual bones can provide them with different mobility relative to each other. According to the degree of mobility, they are divided into:

uniaxial

They ensure the movement of the connected bones only along one axis (only forward and backward or up and down).

Biaxial

Movement in them occurs in two perpendicular planes (for example, in vertical and horizontal, or in longitudinal and transverse).

multi-axle

Such a connection of bones, due to design features, gives them the ability to move along several axes. Multi-axle joints can be three-axle and four-axle.

Axleless

They have flat articular surfaces that allow adjacent bones to make very limited sliding or rotational movements. As a rule, they provide articulation of short bones or bones that require a particularly strong connection.

The shape of the articular surface

Depending on their shape, all joints are divided into several groups. Each of them has its own characteristics - in particular, their shape determines the nature of the movement of the connected bones. Therefore, all groups of joints are associated with the degree of their mobility.

Uniaxial joints are divided according to the shape of the articular surfaces into the following types:

The articular surfaces in this case are located longitudinally, and one of them has the form of an axis, and the other has the form of a cylinder with a longitudinally cut base. A classic example of a cylindrical articular joint is the median atlantoaxial, located in the cervical vertebrae.

blocky

Block-shaped joints in their shape resemble cylindrical ones, but the articular surfaces in them are not located longitudinally, but transversely. To limit the displacement of the bones to the side, they may have special ridges and recesses that prevent freedom of movement. These include the joints of the phalanges of human fingers or the elbow joints of ungulates.

helical

At its core, it is a kind of block joint. The drawing of a helical structure suggests the presence on the surfaces of the epiphysis of one bone of peculiar grooves that enter the corresponding grooves on the epiphysis of the second bone. Thanks to this, it is possible to move in a spiral, from where the second name of this type of joints comes from - spiral.

Biaxial connections are provided by the following forms of articular structures.

elliptical

The connecting surface of one of the bones has the shape of a convex, and the other - a concave ellipse. In the human skeleton, the atlantooccipital joint and the joint connecting the femur and tibia are elliptical.

Condylar

The surface of one bone has the shape of a sphere, and the other is a concave surface in which this sphere is located. The condylar articulation ensures the mobility of the bones in two planes: flexion-extension and right-left rotation. This condylar connection looks like a spherical one. But, unlike it, it does not allow active rotational movements around the vertical axis. An example is the metacarpophalangeal and knee joint.

saddle

Both saddle bones have saddle-shaped recesses at their ends, these recesses being perpendicular to each other. This arrangement gives several more opportunities for movement. For example, the metacarpal-carpal joint of the thumb of humans and primates has a similar design, which makes it possible to “oppose” it to the rest of the fingers of the hands.

The possibility of such a contrast, from the point of view of biologists, has become one of the main reasons for the transformation of apes into humans. The presence of the saddle joint allowed our ancestors to use their hands as an active grasping mechanism for holding various tools.

Multiaxial articulation is carried out using joints of the following form:

Globular

In this case, one of the bones has a ball-shaped head at its end, and the opposite bone has a hollow. As a result, movement is possible in any direction, which makes the ball-and-socket joints the most free in the human body.

Their other name is walnut, because of the similarity of the shape of the spherical head with a walnut. A classic example of a ball and socket joint is the shoulder joint between the scapula and the humerus.

bowl-shaped

It is one of the private forms of a spherical joint. Similarly, the largest human joint, the hip joint, is articulated. In this case, the spherical head is placed in a special "bowl" - the acetabulum. Such a connection allows a person to move the hip in four directions:

• along the frontal axis - flexion-extension (when squatting, raising the leg to the stomach);
• along the sagittal axis - moving the leg to the side and returning it to its original position;
• along the vertical axis - some displacement of the thigh relative to the pelvis when the leg is extended;
• circular rotation of the hip;

Flat

The surfaces of both bones facing each other in this case have a flat or close to it shape. A more precise definition is not “a plane”, but “the surface of a sphere of large section”. Such joints enable the bones to move in all three axes; however, due to the peculiarities of their design, all these movements are extremely limited in amplitude. For the most part, they play an auxiliary, buffer role. An example of such a structure is the intervertebral joints, joints of the foot and hand.

Amphiarthrosis

They are also “tight joints”. A special type of connection, possible with any surface shape. Its distinctive feature is the presence of a short and tightly stretched capsule, which is surrounded on all sides by strong, practically non-stretching ligaments.

The articular surfaces of both interlocking bones are very tightly pressed against each other. This design feature significantly limits their ability to move relative to each other. Amphiarthrosis, for example, is the sacroiliac joint. The purpose of such rigid structures is to absorb shocks and shocks experienced by the bones.

Conclusion

So, we examined what a human joint is, how many there are in our body, what types and characteristics of each joint are, and where they are located.