Kanavel's cardinal signs

Kanavel's sign is a clinical sign found in patients with infection of a flexor tendon sheath in the hand (pyogenic flexor tenosynovitis), a serious condition which can cause rapid loss of function of the affected finger.

The sign consists of four components:
 * 1) the affected finger is held in slight flexion.
 * 2) there is fusiform swelling over the affected tendon.
 * 3) there is tenderness over the affected flexor tendon sheath.
 * 4) there is pain on passive extension of the affected finger.

The sign is named after Allen B. Kanavel who first described them in 1912.