Tenosynovitis refers to an inflammation of the sheath of a tendon and may be acute or chronic, or serous, fibrinous, or purulent, or any combination, according to the exudate. The purulent is usually the result of a secondary infection.

Bursitis, inflammation of the bursa, is usually found in the prepatellar bursa as a result of chronic irritation, and is accompanied by effusion.

Tuberculosis may involve either of the above structures secondarily to disease of the bones and joints.