Contents of the Posterior Fascial Compartment of the Forearm-Stenosing Synovitis of the Abductor Pollicis Longus and Extensor Pollicis Brevis Tendons-Arteries of the Posterior Fascial Compartment of the Forearm-Rupture of the Extensor Pollicis Longus Tendon- “Anatomic Snuffbox”

Contents of the Posterior Fascial Compartment of the Forearm

■■ Muscles: The superficial group includes the extensor carpi radialis brevis, extensor digitorum, extensor digiti minimi, extensor carpi ulnaris, and anconeus. These muscles possess a common tendon of origin, which is attached to the lateral epicondyle of the humerus. The deep group includes the supinator, abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus, and extensor indicis.

■■ Blood supply: Posterior and anterior interosseous arteries

■■ Nerve supply to the muscles: Deep branch of the radial nerve Muscles of the Posterior Fascial Compartment of the Forearm

Stenosing Synovitis of the Abductor Pollicis Longus and Extensor Pollicis Brevis Tendons

As a result of repeated friction between these tendons and the styloid process of the radius, they sometimes become edematous and swell. Later, fibrosis of the synovial sheath produces a condition known as stenosing tenosynovitis in which movement of the tendons becomes restricted. Advanced cases require surgical incision along the constricting sheath.

Arteries of the Posterior Fascial Compartment of the Forearm

The anterior and posterior interosseous arteries arise from the common interosseous artery, a branch of the ulnar artery. They pass downward on the anterior and posterior surfaces of the interosseous membrane, respectively, and supply the adjoining muscles and bones. They end by taking part in the anastomosis around the wrist joint.

Rupture of the Extensor Pollicis Longus Tendon

Rupture of this tendon can occur after fracture of the distal third of the radius. Roughening of the dorsal tubercle of the radius by the fracture line can cause excessive friction on the tendon, which can then rupture. Rheumatoid arthritis can also cause rupture of this tendon.

 “Anatomic Snuffbox”

The anatomic snuffbox is a term commonly used to describe a triangular skin depression on the lateral side of the wrist that is bounded medially by the tendon of the extensor pollicis longus and laterally by the tendons of the abductor pollicis longus and extensor pollicis brevis . Its clinical importance lies in the fact that the scaphoid bone is most easily palpated here and that the pulsations of the radial artery can be felt here.