Anatomy Involved in the Gamekeeper's thumb Injury
Bones and Ligaments
Gamekeeper's thumb results in injury to the Ulnar Collateral ligament (UCL). The UCL attaches the first metacarpal bone to the first proximal phalanx on the medial side of the joint (7). Functionally, the UCL provides stability to the thumb and protects the thumb from hyperabduction.
Muscles
Several muscles are involved thumb motion; however, after a Gamekeeper's Thumb injury, one will notice weakness in pinching or grasping with the thumb. The primary muscle associated with this action is the adductor pollicis. The adductor pollicis has two heads, an oblique and transverse head, and both heads attach to the base of the first proximal phalanx at the medial side (1).
Joint Type
The main joint involved in a Gamekeeper's thumb injury is the metacarpophalangeal (MCP) joint. The MCP joint is a condyloid joint that is capable of flexion, extension, adduction and abduction (10).