Examination
of Joints
When examining a patient, the clinician should assess the normal range of movement of all joints. When the bones of a joint are no longer in their normal anatomic relationship with one another, then the joint is said to be dislocated. Some joints are particularly susceptible to dislocation because of lack of support by ligaments, the poor shape of the articular surfaces, or the absence of adequate muscular support. The shoulder joint, temporomandibular joint, and acromioclavicular joints are good examples. Dislocation of the hip is usually congenital, being caused by inadequate development of the socket that normally holds the head of the femur firmly in position. The presence of cartilaginous discs within joints, especially weightbearing joints, as in the case of the knee, makes them particularly susceptible to injury in sports. During a rapid movement, the disc loses its normal relationship to the bones and becomes crushed between the weightbearing surfaces. In certain diseases of the nervous system (e.g., syringomyelia), the sensation of pain in a joint is lost. This means that the warning sensations of pain felt when a joint moves beyond the normal range of movement are not experienced. This phenomenon results in the destruction of the joint. The knowledge of the classification of joints is of great value because, for example, certain diseases affect only certain types of joints. Gonococcal arthritis affects large synovial joints such as the ankle, elbow, or wrist, whereas tuberculous arthritis also affects synovial joints and may start in the synovial membrane or in the bone. Remember that more than one joint may receive the same nerve supply. For example, both the hip and knee joints are supplied by the obturator nerve. Thus, a patient with disease limited to one of these joints may experience pain in both.
When examining a patient, the clinician should assess the normal range of movement of all joints. When the bones of a joint are no longer in their normal anatomic relationship with one another, then the joint is said to be dislocated. Some joints are particularly susceptible to dislocation because of lack of support by ligaments, the poor shape of the articular surfaces, or the absence of adequate muscular support. The shoulder joint, temporomandibular joint, and acromioclavicular joints are good examples. Dislocation of the hip is usually congenital, being caused by inadequate development of the socket that normally holds the head of the femur firmly in position. The presence of cartilaginous discs within joints, especially weightbearing joints, as in the case of the knee, makes them particularly susceptible to injury in sports. During a rapid movement, the disc loses its normal relationship to the bones and becomes crushed between the weightbearing surfaces. In certain diseases of the nervous system (e.g., syringomyelia), the sensation of pain in a joint is lost. This means that the warning sensations of pain felt when a joint moves beyond the normal range of movement are not experienced. This phenomenon results in the destruction of the joint. The knowledge of the classification of joints is of great value because, for example, certain diseases affect only certain types of joints. Gonococcal arthritis affects large synovial joints such as the ankle, elbow, or wrist, whereas tuberculous arthritis also affects synovial joints and may start in the synovial membrane or in the bone. Remember that more than one joint may receive the same nerve supply. For example, both the hip and knee joints are supplied by the obturator nerve. Thus, a patient with disease limited to one of these joints may experience pain in both.
Damage
to Ligaments
Joint ligaments are very prone to excessive stretching and even
tearing and rupture. If possible, the apposing damaged surfaces of the ligament
are brought together by positioning and immobilizing the joint. In severe
injuries, surgical approximation of the cut ends may be required. The blood
clot at the damaged site is invaded by blood vessels and fibroblasts. The fibroblasts
lay down new collagen and elastic fibers, which become oriented along the lines
of mechanical stress
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