Injuries comprise contusions, sprains, dislocations, and penetrating wounds. The main diseases affecting the joints are rheumatic fever, rheumatoid arthritis, osteoarthritis, and gout. Permitting movement in all directions, the ball and socket joint features the rounded head of. Angular movement, if it occurs forward, is called flexion if backward, extension if away from the body, abduction and toward the median plane of the body, adduction.īecause of their location and constant use, joints are prone to stress, injury, and inflammation. There are six types of freely movable diarthrosis (synovial) joints: Ball and socket joint. Joints can move in four ways: gliding, in which one bony surface glides on another without angular or rotatory movement angulation, occurring only between long bones, increasing or decreasing the angle between the bones circumduction, occurring in joints composed of the head of a bone and an articular cavity, the long bone describing a series of circles, the whole forming a cone and rotation, in which a bone moves about a central axis without moving from this axis. Joints are also grouped according to their motion: ball-and-socket ( enarthrodial) hinge ( ginglymoid) condyloid pivot ( trochoid) gliding ( arthrodial) and saddle. A diarthrodial joint is one in which the adjoining bone ends are covered with a thin cartilaginous sheet and joined by a joint capsule lined by a synovial membrane, which secretes synovial fluid. An amphiarthrodial joint is one having a fibrocartilaginous disk between the bony surfaces (symphysis), such as the symphysis pubis or one with a ligament uniting the two bones (syndesmosis), such as the tibiofibular articulation. A synarthrodial joint is one in which the two bones are separated only by an intervening membrane, such as the cranial sutures. A joint is classified as immovable ( synarthrodial), slightly movable ( amphiarthrodial), or freely movable ( diarthrodial). A joint usually has a thin, smooth articular cartilage on each bony surface and is enclosed by a joint capsule of fibrous connective tissue. Some joints are fixed or immobile attachments of bones other joints allow the bones to move along each other.
0 Comments
Leave a Reply. |