Thumb Ulnar Collateral Ligament (UCL) Injury

This condition, also called skier's thumb, is an acute sprain or tear of the ulnar collateral ligament (UCL) on the ulnar side of the metacarpal-phalangeal (MCP) joint of the thumb.

A related condition, called gamekeeper's thumb, is a chronic injury that develops over time from repeated stretching of the UCL.