Corpus: Trapezium bone

The trapezium bone is located on the radial side of the distal wrist (Carpus); it borders ulnarly on the trapezoid bone, with which it is in joint connection. On the palmar side, there is a small bony protrusion, the tubercle of the trapezium. Proximally, the trapezium articulates with the distal surface of the scaphoid bone and is thus involved in the midcarpal joint. Distally, the bone borders on the first metacarpal bone and forms with it the thumb saddle joint, a part of the carpometacarpal joint.

In the vicinity of the trapezium bone, four potential ossification centers can lead to the formation of accessory bones. These are the os trapezium secundarium, the os epitrapezium, the os praetrapezium, and the os paratrapezium.

Clinically, the trapezium bone is relevant in the context of rhizarthrosis, where it may be surgically removed during a trapeziectomy.