Posterior region of forearm

The posterior region of forearm is defined as the region extending from the lateral epicondyle of the humerus proximally to the dorsal aspect of the wrist distally. It is bounded medially by the subcutaneous border of the ulna and laterally by the radius and brachioradialis muscle.

This region contains the muscles, nerves, and blood vessels responsible for extension of the wrist and fingers, as well as supination of the forearm. The muscles are organized into superficial and deep layers.

Key Musculature

The superficial layer includes:

• Extensor Carpi Radialis Longus and Brevis

• Extensor Digitorum

• Extensor Digiti Minimi

• Extensor Carpi Ulnaris

The deep layer comprises:

• Supinator

• Abductor Pollicis Longus

• Extensor Pollicis Brevis

• Extensor Pollicis Longus

• Extensor Indicis

Neurovascular Supply

The primary innervation to the posterior forearm is provided by the radial nerve. Distal to the supinator muscle, the radial nerve divides into a superficial sensory branch and a deep motor branch (posterior interosseous nerve). The posterior antebrachial cutaneous nerve, a branch of the radial nerve, provides sensation to the overlying skin of the posterior forearm.

Arterial supply is primarily from the posterior interosseous artery, which accompanies the posterior interosseous nerve and supplies the deep extensor muscles.