What is a sprain of the ulnar collateral ligament of the thumb?
A sprain is an injury to a ligament. In this case, it is an injury to the ulnar collateral ligament (UCL) of the metacarpophalangeal (MCP) joint of the thumb. Because the purpose of ligaments is to stabilize the bones within a joint, significant injury to this ligament can cause instability of the thumb. This type of injury may affect the athlete’s ability to grip, throw, or catch an object. For an athlete, this type of injury can be devastating.
