Tendon sheath

A tendon sheath is a layer of synovial membrane around a tendon. It permits the tendon to stretch and not adhere to the surrounding fascia. It contains a lubricating fluid that allows for smooth motions of the tendon during muscle contraction and joint movements.

It has two layers:
 * synovial sheath
 * fibrous tendon sheath

Fibroma of the tendon sheath has been described.