S63.64 - Sprain of metacarpophalangeal joint of thumb S63.6 - Other and unspecified sprain of finger(s) S63.64 - Sprain of metacarpophalangeal joint of thumb S63.641 - Sprain of metacarpophalangeal joint of right thumb S63.642 - Sprain of metacarpophalangeal joint of left thumb S63.649 - Sprain of metacarpophalangeal joint of unspecified thumb