Page:Structure and functions of the body; a hand-book of anatomy and physiology for nurses and others desiring a practical knowledge of the subject (IA structurefunctio00fiskrich).pdf/199

 injured. In dislocation the head may be behind or in front of the acetabulum. Impacted hip, where the neck of the femur has, in a fall, been driven into the head, is common in old people. Sometimes, especially in young children, the bone is infected, osteomyelitis. Sarcoma occurs. Most tubercular disease of the hip originates at the upper extremity of the femur, tuberculosis generally starting in the head and then attacking the capsule and the soft parts of the joint. If neglected, shortening of the leg may result, in which case the bone has to be broken and set at an angle in order to enable the child to walk.

—Right knee-joint, posterior view. (Leidy.)

—Right knee-joint, showing internal ligaments: 2, anterior crucial ligament; 3, posterior crucial ligament; 4, transverse ligament; 6, 7, semilunar fibrocartilages. (Leidy.)

Occasionally a bit of cartilage gets broken off in the knee-joint and wedged between the bones, so that the joint cannot be straightened. This is ''dislocation of the semilunar cartilage'' and necessitates an operation for removal of the piece. The cartilage will eventually be replaced by fibrous tissue and in a few months the leg