Bennett fracture is a type of partial broken finger involving the base of the thumb, and extends into the carpometacarpal (CMC) joint.

[citation needed] Symptoms of Bennett fracture are instability of the CMC joint of the thumb, accompanied by pain and weakness of the pinch grasp.

The patient will often manifest a weakened ability to grasp objects or perform such tasks as tying shoes and tearing a piece of paper.

Because of the aforementioned biomechanical features, Bennett fractures nearly always require some form of intervention to ensure healing in the correct anatomical position and restoration of proper function of the thumb CMC joint.

[citation needed] Some authors have recently made an assertion against popular belief that the APL tendon is not a deforming force on the Bennett fracture.

[3] Though these fractures commonly appear quite subtle or even inconsequential on radiographs, they can result in severe long-term dysfunction of the hand if left untreated.

Bennett said his fracture "passed obliquely across the base of the bone, detaching the greater part of the articular surface, and the separated fragment was very large and the deformity that resulted there-from seemed more a dorsal subluxation of the first metacarpal".