injuries poisoning
Ulnar Collateral Ligament Sprains
Introduction
Ulnar collateral ligament sprains of the thumb are common and sometimes disabling. (See also Overview of Sprains and Other Soft-Tissue Injuries .) The ulnar collateral ligament connects the base of the thumb's proximal phalanx to the thumb's metacarpal bone on the ulnar aspect of the joint. The usual injury mechanism is radial deviation of the thumb, commonly caused by falling on the hand while holding a ski pole. Sometimes when the ligament tears, it avulses part of the proximal phalanx at the ligament attachment. Initially, patients have pain and point tenderness on the ulnar aspect of the thumb metacarpal joint. Long-term complications can include weakness and instability of the joint. 