"Snapping bottom": subluxation of the tendon of the long head of the biceps femoris muscle.

Subluxation of the tendon of origin of the long head of the biceps femoris muscle (or snapping bottom) is a rare, previously unreported degeneration of the tendinous attachments of the muscle at the ischial tuberosity. It occurs in a patient who wears out this attachment through a lifetime of hyperflexion hip movements, such as are required in bending to reach the floor. The snapping of the tendon across its point of origin causes pain and swelling in the buttock. In the older nonathlete, if conservative measures fail, the treatment of choice is simple tenotomy. The condition should not be confused with weaver's bottom (ischiogluteal bursitis), even though it may be a cause for that bursitis.