Corpus: Trapezoid bone

The trapezoid bone is located roughly in the middle of the distal wrist (carpus); it is adjacent radially to the trapezium bone and ulnarly to the capitate bone. It articulates with both bones. Proximally, the trapezoid bone articulates with the distal surface of the scaphoid bone and is thus involved in the midcarpal joint. Distally, the bone is adjacent to the metacarpal bone II and forms part of the carpometacarpal joint.

Occasionally, an accessory bone, the trapezoid bone secundarium, develops at the radial wrist.