First metacarpal

The first metacarpal bone or the metacarpal bone of the thumb is the first bone proximal to the thumb. It is connected to the trapezium of the carpus at the first carpometacarpal joint and to the proximal thumb phalanx at the first metacarpophalangeal joint.First metacarpal bone of the left hand (shown in red). Animation.First metacarpal bone of the left hand. Close up.Palmar view of the left hand (first metacarpal shown in yellow).Dorsal view of the left hand (first metacarpal shown in yellow).Fracture of the first metacarpal (Rolando's fracture).First metacarpal bone. Deep dissection. The first metacarpal bone or the metacarpal bone of the thumb is the first bone proximal to the thumb. It is connected to the trapezium of the carpus at the first carpometacarpal joint and to the proximal thumb phalanx at the first metacarpophalangeal joint. The first metacarpal bone is short and thick with a shaft thicker and broader than those of the other metacarpal bones. Its narrow shaft connects its widened base and rounded head; the former consisting of a thick cortical bone surrounding the open medullary canal; the latter two consisting of cancellous bone surrounded by a thin cortical shell.