Bursa A closed sac with synovial lining and joint fluid within Yoga girl , generally separating a bone from a tendon. The bursae are thought to have evolved from Yoga girl joints, since they have the same basic structure, and to have been retained because they prevent the tendon from bruising the bone, and the bone from fraying the tendon. The Latin word bursa means purse. bursitis Inflammation of a bursa see above, which can become quite painful.
Examples are Achilles bursitis between the tendon and the ankle bone, prepatellar bursitis external to the kneecap, pes anserinus bursitis separating the sartorius, gracilis, and semitendinosus tendons from the tibia just below the inner knee, and ischial bursitis between the bones on which one sits and the hamstring muscles that attach to them.
Carpal tunnel syndrome Entrapment of the median nerve in a tight-fitting passageway between the bones of the wrist. Tendons also pass through the carpal tunnel and injure the nerve when they become inflamed or swollen e.g when swelling in pregnancy congests the compartment.