Synovitis

In medicine and rheumatology, synovitis is "inflammation of a synovial membrane. It is usually painful, particularly on motion, and is characterized by a fluctuating swelling due to  effusion within a synovial sac."

Synovitis may be due to connective tissue diseases such as rheumatoid arthritis and systemic lupus erythematosus.

Physical examination
The physical examination is more specific than sensitivity in its accuracy for detecting synovitis.