Bennett and Rolando fractures of the thumb metacarpals

(A) A typical Bennett fracture is a unicondylar fracture of the base of the first metacarpal with the fracture fragment consisting of the volar ulnar corner of the proximal metacarpal.
(B) A Rolando fracture is multi-fragmentary, with the entire articular base of the metacarpal being involved. By definition, no portion of the metacarpal shaft is in continuity with the carpometacarpal joint.