Interosseous membrane of forearm

Origin: forearm fascia

The interosseous membrane is a derivative of the forearm fascia (fascia antebrachii). This fascia forms a dense "cuff".

Deep within the limb, the fascia gives off intermuscular septa and the interosseous membrane (membrana interossea antebrachii), which extends toward the borders of the radius and ulna.

Distally, the fascia forms:

• Extensor retinaculum (retinaculum extensorum) — located on the posterior aspect.
• Flexor retinaculum (retinaculum flexorum) — also known as the transverse carpal ligament, which forms the roof of the carpal tunnel.

Structure and apertures of the interosseous membrane

The structure of the membrane includes the oblique cord (chorda obliqua).

The membrane has two apertures:

• Proximal aperture.
• Distal aperture.

Vessels and nerves pass through these apertures.

Topography: posterior fascial compartment of the forearm

The interosseous membrane participates in the formation of the posterior fascial compartment of the forearm (compartimentum antebrachii posterius).

The walls of this compartment are formed as follows:

• Anterior wall — forearm bones and interosseous membrane.
• Posterior wall — deep fascia of the forearm.
• Lateral wall — posterior radial intermuscular septum.
• Medial wall — fusion of the deep fascia with the posterior border of the ulna.

Relationship to forearm muscle groups

Forearm muscles (mm. antebrachii) are divided into several groups:

• Anterior group (flexores, pronatores) — flexors and pronators.
• Posterior group (extensores, supinatores) — extensors and supinators.
• Lateral (radial) group — occupies an intermediate position.

All muscles are surrounded by the fascia antebrachii, which forms intermuscular septa and the interosseous membrane (membrana interossea antebrachii).

• Brachioradialis muscle (m. brachioradialis) originates from the lateral supracondylar ridge of the humerus and the lateral intermuscular septum, attaching to the styloid process of the radius. It flexes the forearm and assists in pronation and supination, returning the hand to a neutral position. It is innervated by the radial nerve (n. radialis, C5–C7) and supplied by the radial and radial collateral arteries (a. radialis, a. collateralis radialis).

• Supinator muscle (m. supinator) originates from the lateral epicondyle of the humerus, the radial collateral and annular ligaments of the radius (lig. collaterale radiale, lig. anulare radii), and the crest of the ulna. It attaches to the proximal third of the radius laterally and anterolaterally, and supinates the forearm. It is innervated by the deep branch of the radial nerve (C6–C7) and supplied by the recurrent radial and posterior interosseous arteries (a. recurrens radialis, a. interossea posterior).

Class and exam questions

What else to study on this topic

• Forearm fascia (fascia antebrachii)
• Posterior fascial compartment of the forearm
• Forearm muscles (mm. antebrachii)
• Carpal tunnel and tendon retinacula

Other topics in the "Anatomical Structures" section

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.