The proximal transverse arch is at the level of the carpometacarpal joint with the keystone being the capitate. It is a relatively fixed arch, remaining arched even when the hand is open.

The distal transverse arch is at the level of the metacarpophalangeal joints with the keystone being the 2^nd and 3^rd metacarpals. It is relatively mobile. The 1^st, 4^th, and 5^th metacarpals rotate around the 2^nd and 3^rd metacarpals to either flatten or increase its arc.

Carpals | Metacarpals | Phalanges |
Hand Arches | Bone and Joint Structure | Help | Hand Kinesiology

Lorie Richards and Janice Loudon, October 1997