Posterior compartment of the forearm Posterior compartment of the forearm The posterior compartment of the forearm (or extensor compartment) contains twelve muscles which are chiefly responsible for extension of the wrist and digits, and supination of the forearm. It is separated from the anterior compartment by the interosseous membrane between the radius and ulna. There are generally twelve muscles in the posterior compartment of the forearm, which can be further divided into a superficial, intermediate, and deep layer. Most of the muscles in the superficial and the intermediate layers share a common origin which is the outer part of the elbow, the lateral epicondyle of
Posterior compartment of the forearm muscles because they both arise within the forearm and they both move the forearm. Extensor tendons pass through the extensor retinaculum at wrist joint in 6 synovial sheaths, also referred to compartments. The supinator and the anconeus are the two muscles in the posterior compartment of the forearm that do not pass through wrist extensor compartments. The muscles of the posterior compartment of the forearm are innervated by the radial nerve and its branches. The radial nerve arises from the posterior cord of the plexus. The somatomotor fibers of the radial nerve branch from the main radial nerve at the