The Bennett fracture is an intraarticular fracture of the base of the first metacarpal. The fracture must involve the first carpometacarpal joint to be called a Bennett fracture. The action of the abductor pollicis longus causes distraction of the fracture fragments. The volar base of the first metacarpal stays with the trapezium.

A	Oblique radiograph of the hand. There is an intraarticular fracture at the base of the first metacarpal.
B	PA radiograph of the first digit. This view better defines the Bennett fracture.

Links to online textbooks:

• Wheeless' Orthopedics: discussion of the Bennett fracture

Links to online cases:

• University of South Australia
• Emedicine.com

References:

• Oosterbos CJ, de Boer HH: Nonoperative treatment of Bennett's fracture: a 13-year follow-up J Orthop Trauma. 1995 Feb;9(1):23-7.           [See related articles]
• Kahler DM: Fractures and dislocations of the base of the thumb J South Orthop Assoc. 1995 Spring;4(1):69-76.           [See related articles]