Inflammation of a tendon sheath. Causes include trauma, tendon stress, bacterial disease (gonorrhea, tuberculosis), rheumatic disease, and gout. Common sites are the shoulder capsule, hip capsule, hamstring muscles, and Achilles tendon. The tendon sheaths become inflamed and painful, and accumulate fluid. Joint mobility is usually reduced. Friction rubs may be felt or heard (with a stethoscope) on movement. Calcium deposits may occur in the tendon and its sheath, leading to opacities on radiographs of the affected area. (Saunders Dictionary & Encyclopedia of Laboratory Medicine and Technology, 1984)