Avulsion injuries of the hand and wrist

Injuries of the hand and wrist are frequently encountered in radiology. Avulsions of the hand and wrist are a heterogeneous group of injuries, but they often have a characteristic imaging appearance that relates to the intricate bone and soft-tissue anatomy and the mechanism of injury. The imaging appearance and this intricate form and function dictate treatment of hand and wrist avulsions. This article reviews frequently and infrequently encountered avulsion injuries and describes abnormalities that may mimic the imaging appearance of avulsions. Specifically discussed entities include the Bennett and reverse Bennett fracture, ulnar collateral ligament avulsion, radial and ulnar styloid process avulsion, triquetral avulsion, mallet and jersey finger, central slip avulsion, and acute and chronic volar plate avulsion injuries. Uncommon avulsion injuries are also described and include avulsions of the scapholunate ligament, extensor carpi radialis longus and brevis tendons, trapeziometacarpal ligament, radial collateral ligament, and flexor digitorum profundus tendon. Emphasis is placed on the relevant anatomy and typical imaging findings for each diagnosis, with pertinent clinical history, pathophysiologic evaluation, and treatment discussed briefly. Understanding the anatomy and expected imaging findings can aid the radiologist in recognizing and characterizing these injuries.