Antebrachial fascia is the deep fascia encasing forearm muscles and forming intermuscular septa.
The antebrachial fascia is the deep fascia of the forearm. It is a strong, fibrous connective tissue layer that encloses the muscles of the forearm and helps form the boundaries of the anterior (flexor-pronator) and posterior (extensor-supinator) compartments. It also plays a role in forming specialized structures such as the flexor and extensor retinacula at the wrist.
The antebrachial fascia surrounds the entire forearm, extending from the brachial fascia at the elbow to the palmar fascia and dorsal hand fascia at the wrist. It lies beneath the skin and superficial fascia, superficial to the muscles, vessels, and nerves.
Compartment | Muscle Groups | Innervation | Function |
---|---|---|---|
Anterior (Flexor-Pronator) | Pronator teres, FCR, PL, FCU, FDS, FDP, FPL, PQ | Median nerve (main), Ulnar nerve (FCU, medial FDP) | Flexion of wrist/fingers, forearm pronation |
Posterior (Extensor-Supinator) | Brachioradialis, ECRL, ECRB, ED, EDM, ECU, Supinator, APL, EPB, EPL, EI | Radial nerve (deep branch → PIN) | Extension of wrist/fingers, forearm supination |
The fascia itself has minimal sensory innervation, though adjacent nerves (e.g., medial antebrachial cutaneous nerve) may supply overlying skin and superficial fascia.
The antebrachial fascia influences the contour and firmness of the forearm. It is particularly thick in the distal third, where it anchors muscles and transitions into the carpal retinacula.
Arises from mesenchymal connective tissue of the limb bud. Its specialization in the distal forearm (retinacula) reflects functional demands of tendon control and muscle force routing during hand and wrist activity.
In quadrupeds, the antebrachial fascia is generally thinner and more elastic. In humans, it has adapted to support fine motor control, tendon containment, and wrist stability necessary for tool use and manual dexterity.