Joints are 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:
- cartilaginous (hyaline, 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.
Classification of human joints involves dividing them into several independent groups, defined by a similar feature. Conditionally can be distinguished:
- 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, spherical, flat;
- on possible movement.
Variety of combinations
Different cartilaginous surfaces that work together determine the simplicity or complexity of the connection structure. Classification of joints (table by anatomy) allows you to divide them into simple, complex, combined, complex.
| Classification of the structure of the joints | Characteristic | Name of joints |
| Simple | Formed by 2 bones | Interphalangeal |
| Complex | Formed from 3 or more bones | Elbows |
| Complex | Have an additional disc or meniscus | Knees |
| Combined | Work in pairs, at the same time | Temporomandibular |
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 of the wrist joint 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 threeself compound 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 connection. 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 synergy is the right and left temporomandibular joints.
Possible rotation
Articular connections 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.
- Single-axis - 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 shapes
Classification of joints by shapequite extensive. Each joint has evolved to reduce workload and increase manpower.
- Cylindrical. It has a single axis of rotation - 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.
- Block-shaped - uniaxial joint. The name is directly defining its structure. One surface is ridge-shaped, 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 the elbow joint.
- Ellipsoid - rotates along two axes - vertical and sagittal. Movement at this joint provides flexion, extension, adduction, and abduction (the 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 is the knee joint. The classification also highlights other condylar compounds. For example, the temporomandibular joint.
- Saddle shape. 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 mostmassive in the body - 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 distinguished by a smaller amplitude of possible movements.
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 lower jaw
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 to the joint capsule.
Do your joints hurt?
Joints in the human body perform an important function - movement. When they are he althy, the amplitude of actions is not disturbed. Life without feeling pain and discomfort is much more pleasant than with them.
There are various diseases of the joints. The classification divides them into groups according to specific symptoms, the complexity of the process and the nature of the course (acute, subacute, chronic). Pathologically isolated:
- arthralgia (joint pain of a fixed or volatile nature);
- arthritis (inflammatoryprocesses);
- arthritis (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, such as tubercle bacillus, or evolutive. Joint diseases are especially distinguished by 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 exercise), 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 not related to 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 lung diseases (sarcoidosis) andnervous 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
Classification of joints affected by arthrosis cannot be limited to their singularity or a certain 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. Distinguish setneonatal diseases. These include: arthrogryposis, pseudoarthrosis of the lower leg, congenital dislocation of the hip or patella, hip dysplasia, Marfan's syndrome (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, now it is fixed at 40.
To avoid serious complications and live a long life without restricting your movements, it is important to monitor your general he alth and carry out timely prevention. It consists in controlling body weight, proper nutrition, eliminating bad habits and moderate physical activity.
