Bennett fracture of the thumb

A Bennett fracture of the thumb is an oblique, intra-articular fracture of the thumb metacarpal base. The smaller proximal fragment of the metacarpal shaft includes the palmar and ulnar corner of the metacarpal base and is fixed to the base of the index finger metacarpal and the trapezium by virtue of the anterior oblique ligament. The larger fragment of the metacarpal shaft is displaced radially, proximally and dorsally by the pull of the abductor pollicis longus (APL) that inserts on the dorsal radial corner of the metacarpal base. This is an unstable fracture pattern that requires fixation after reduction of the fracture.