Ulnar Collateral Ligament Injury Symptoms and Treatment
A gamekeeper's thumb, also called a skier's thumb, is an injury to one of the important ligaments at the base of the thumb joint. The injury involves the ulnar collateral ligament (UCL), a band of tough, fibrous tissue that connects the bones at the base of the thumb. This ligament prevents the thumb from pointing too far away from the hand.
Source: Verywell Health