Bursitis is inflammation of which structure?

• A. Inflammation of the fluid-filled sac (bursa) that lies between a tendon and skin, or between a tendon and bone
• B. Inflammation of a joint capsule
• C. Inflammation of a tendon
• D. Inflammation of the synovial membrane

Answer: (A)

Bursitis is inflammation of the bursa, the small fluid-filled sac that cushions and reduces friction between moving structures, typically between a tendon and the overlying skin or between a tendon and bone. When the bursa becomes inflamed, movement can cause pain and swelling because the cushion is irritated. This distinguishes bursitis from other inflammatory conditions: inflammation of the joint capsule is capsulitis, inflammation of a tendon is tendinitis, and inflammation of the synovial membrane is synovitis. The description that fits bursitis is the inflammation of the fluid-filled sac between a tendon and skin or between a tendon and bone.