Joints unite human skeletal bones into a single whole. More than one hundred and eighty of such nodal connections help people to perform various actions. Together with the ligaments and bones, they represent a harmonious system of the motor apparatus. The joints are comparable to the joints. Their task is to ensure smooth, or softening, due to the shock-absorbing properties. If they are absent, friction will occur at the joints, leading to the destruction of bone tissue, which is very painful and dangerous.
In the human body, the joints play the most important role. They maintain the functional integrity of the skeleton, set in motion its individual parts, and serve as auxiliary elements for the movement of the body in space. In medicine, there is such a thing as the range of motion in the joints. Details are provided below.
Human anatomy, structure and function of joints
Joints are nodes for connecting bones, providing the human skeleton with mobility. Any actions are primarily determined by the participation of these elements, so their condition is especially important for the body. The joint is considered a two-layer bag surrounding the joints of individual parts of the skeleton. Its main functions are to ensure the tightness of the cavity of the node and the production of synovial fluid, which plays a unifying role in the articulation of bones.
The ends of all the components of the skeleton in the areas of the joints differ in a special shape: one of them has a bulge, and the other has a special recess. The first part is called the articular head, and the concave - the fossa. The surfaces of the recesses, as well as the heads, are covered with an elastic smooth cartilage that reduces friction and plays the role of a shock absorber during tremors and shocks during movements.
Specialists use goniometers in order to establish the functionality of nodal connections. This allows you to identify their condition and prescribe appropriate treatment. It turns out that the measured range of motion in the joints, in degrees.
Cartilage
Cartilage consists of connective tissue fibers that are located in the matrix. The latter is a substance formed from glycosaminoglycans. The matrix is responsible for cartilage nutrition and repair of damaged fiber. A similar structure may resemble a sponge. For example, at rest, it can absorb liquid, and during movements it squeezes it into the joint cavity, providing lubrication.
What limits the range of motion?
On the edges of the articular surface or on the bones located near them there are protrusions that limit the amplitude of movements. For example, the tubercle of the humerus, which is in contact with the beginning of the scapular process, limits the functionality of the hands. Another important element of the joints are ligaments, which are bundles of fibers that hold the bones in a special position. They are mounted so that they provide reliable fixation of the components of the ridge and in no way impede their movement.
Ligament elasticity
The elasticity of the ligaments makes it possible to make movements of different amplitudes without exposing a person to danger of injury. True, in the case of ultimate loads, the fibers are able to detach from the attachment point and tear apart as well. With age, their elasticity is much less. The most flexible are the ligaments of children, which can stretch ten percent of their length. In middle-aged people, they are only five percent elongated. In older people, elasticity becomes almost zero.
The functioning of the joints is impossible without the muscles that set them in motion. Despite the fact that muscle tissue is not an integral part of the connective nodes, they cannot function without them.
What is the normal range of motion in the joints is of interest to many.
Types of joints
In the human body there are several types of joints, classified by type of revolutions. The most mobile are considered spherical, having a large number of rotation axes. With their help, movements are carried out with flexion and extension, abduction and bringing parts of the body to the desired position, as well as turns outward and inward and circular rotations. An example of such joints are the shoulder nodal joints.
Ellipsoidal perform such functions as extension and bending, abduction and adduction, circular movements. These include the wrist joint.
A smaller range of motion is provided by block and cylindrical joints. For example, the knee and ankle nodes usually perform only the function of flexion and extension.
Flat joints are represented in anatomy in the form of bone joints that do not have heads or pits. Such nodal elements make it possible to make movements in various directions, however, with a small amplitude. Similar joints are located between the bones of the tarsus and in the wrist. Compounds of two bones are called simple, three or more - complex. The number of ligaments is inversely proportional to joint mobility. For example, spherical are fastened with only one bunch.
The special structure of the joints of the spinal column. The movement of the vertebrae is carried out due to the deformation of the intervertebral elastic discs, which not only provide mobility, but also shock absorbing tremors with shock and shock. The movement of the column is carried out in three directions: when bending and unbending, turning and tilting to the sides. Joints of the chest are located in the areas of connection of the ribs with the sternum and the spine. They are flat, with little mobility. Moreover, the sterno-costal joints are also prone to a complete loss of mobility and overgrowth of cartilaginous tissues.
Range of motion in the hip joint
Flexion within the hip joint can be measured while on the back or on a healthy side. The goniometer is attached to the outer surface of the connection. The screw of the device is at the level of a large skewer. One branch runs along the external femoral surface, and the other along the lateral part of the trunk.
The bending angle in healthy people is different. Subcutaneous fatty tissue and muscles play a role here. Therefore, for comparison, the bending angle is measured in the other leg. What is the range of motion in the joints?
Bending to sixty degrees is allowed. In that case, if the patient is able to straighten his leg to such an indicator, indicate hip flexion contracture equal to 160 °. The doctor focuses on the patient's capabilities. When the flexion reaches one hundred and twenty degrees, then note hip flexion contracture equal to 120 °. As for the norm of range of motion in the hip joint, it ranges from one hundred twenty to one hundred and sixty degrees.
Extension within the hip joint is determined when the patient is in a position on the abdomen or on a healthy side. The goniometer is located on the outer surface of the trunk and thigh. The range of motion in the joints is individual for each person and directly depends on the degree of elasticity of the ligaments. The angle between the trunk and thigh can be one hundred sixty-five degrees. In order for the measurement to turn out correct, you need to make sure that the pelvis does not lean forward or back. For this, a healthy leg must be straight. The physician assistant must fix the pelvis. Extension-flexion is normal: 10/0/130 degrees.
Range of motion in the knee joint
As part of the measurement of flexion, the patient can lie on his back, as well as on his stomach or on his side, depending on the performance of the elements being tested. The goniometer is applied from the outer surface of the legs, the screw is installed at the height of the joint space of the joint. Flexion in a healthy knee node is possible up to forty-five degrees, and extension is up to one hundred and eighty. Normally, this value is 5/0/140 degrees.
In the event that flexion is possible up to sixty degrees, and extension - up to one hundred fifty five, it should be noted contracture of the knee joint equal to 155 °. In this case, the range of motion is noted in the range from 155 to 60. As for healthy knee joints, in them the indicator ranges from one hundred eighty to forty-five degrees.
Abduction and adduction in the knee connecting element is possible for some diseases or after injuries as a result of damage to the ligamentous apparatus.
Forearm area
The range of motion in the shoulder joint is also checked quite often. Norm indicators:
- extension - 35 degrees,
- bending - 95-100 degrees,
- abduction - 90 degrees (fixed blade),
- reduction - 25-30 degrees,
- pronation and supination with a lowered or retracted arm - 90 degrees.
Joint disease prevention
First of all, you need to track your weight. Bones are not designed for heavy loads. If you do not strengthen them, but destroy them by eating harmful food, then all the more they will be damaged. Overweight provokes diseases of the hip joint and spine. It is necessary, in addition to exercises, to walk a lot. Daily walks on the steps are of great benefit.
It is extremely important to avoid wearing weights, especially when there are prerequisites for the occurrence of joint diseases. It is forbidden to wear a high heel. Do not recommend taking pain medication without consulting a doctor.
As you can see, measuring the range of motion in the joints is an important procedure in the treatment of the musculoskeletal system.