Figurę 4-46. Palmar adduction of the thumb.
Figurę 4-45. Palmar abduction of the thumb.
Figurę 4-47. Radial abduction of the thumb.
Figurę 4-44. A, Hxtension of the ihumb. B, Side view.
Chapter 4_Hand and Wrist 131
swelling over the joint can be an indication of fracture, degenerative or rheumatoid arthritis, Tenderness to the side of the extensor tendon can be a sign of an injury to the restraining hood of the extensor mechanism. If this hood is aliowed to stretch out, the extensor tendon will sublux into the opposite interspace between the metacarpal heads.
Injuries to the collateral ligaments of the MCP joint of the thumb are common. Of these, sprains of the ulnar collateral ligament, often called $kiery$ thumb or game-keepers thumb, are particularly frequent. The finding of tenderness on the appropriate side of the thumtfs MCP joint suggests such an injury. Stability testing of the MCP joints of the thumb and fingers is described in the Stability Testing section.