Extensor tendon compartments of the wrist

Extensor tendon compartments of the wrist
Drawing of the back of the wrist showing the extensor compartments
Anatomical terminology

Extensor tendon compartments of the wrist are anatomical tunnels on the back of the wrist that contain tendons of muscles that extend (as opposed to flex) the wrist and the digits (fingers and thumb).

The extensor tendons are held in place by the extensor retinaculum. As the tendons travel over the posterior (back) aspect of the wrist they are enclosed within synovial tendon sheaths. These sheaths reduce the friction to the extensor tendons as they traverse the compartments that are formed by the attachments of the extensor retinaculum to the distal (far end) of the radius and ulna.