Origin and Course
The posterior interosseous artery originates from the common interosseous artery (a. interossea communis). The common interosseous artery is a short trunk branching off the ulnar artery (a. ulnaris) near the upper border of the forearm, which quickly divides into the anterior and posterior interosseous arteries.
The a. interossea posterior enters the posterior compartment of the forearm through an aperture in the interosseous membrane (membrana interossea) and courses among the extensor muscles. On cross-sections of the forearm, the posterior interosseous artery and veins (a. et v. interossea posterior) are consistently identified.
Topography and Neurovascular Bundle
In the posterior region of the forearm, the neurovascular bundle includes:
- Deep branch of the radial nerve (r. profundus n. radialis).
- Posterior interosseous artery (a. interossea posterior).
- Posterior interosseous nerve (n. interosseus posterior) — the continuation of the deep branch of the radial nerve.
- Accompanying veins.
The entry pathways of these structures into the compartment differ: the vessels emerge through the proximal aperture of the interosseous membrane, whereas the nerve passes through the supinator canal (canalis supinatorius), wrapping around the radius.
Syntopy: The a. interossea posterior lies medial to the nerve.
Branches and Contribution to Vascular Networks
Along its course, the posterior interosseous artery communicates with anastomotic networks of the upper limb:
- Posterior interosseous recurrent artery (a. interossea recurrens) — an early branch of the posterior interosseous artery. It ascends toward the lateral epicondyle and anastomoses with the middle collateral artery (a. collateralis media).
- Dorsal carpal network (rete carpi dorsale). Distally, the posterior interosseous artery contributes to this network. The dorsal carpal network is also formed by the dorsal carpal branches of the radial and ulnar arteries. Three dorsal metacarpal arteries (aa. metacarpeae dorsales) arise from the network, which give rise to the dorsal digital arteries (aa. digitales dorsales) near the metacarpal heads. The network connects with the deep palmar arch via perforating branches.
Blood Supply to Forearm Muscles
The posterior interosseous artery supplies several muscles in the forearm:
- Supinator (m. supinator).
- Abductor pollicis longus (m. abductor pollicis longus).
- Extensor pollicis longus (m. extensor pollicis longus).
- Extensor digitorum (m. extensor digitorum).
- Extensor indicis (m. extensor indicis).
- Extensor digiti minimi (m. extensor digiti minimi).
- Extensor carpi radialis brevis (m. extensor carpi radialis brevis).
- Extensor carpi ulnaris (m. extensor carpi ulnaris).
Clinical Significance and Collateral Circulation
In the distal third of the forearm, the anterior interosseous artery (a. interossea anterior) reaches the posterior compartment by passing from anterior to posterior through the interosseous membrane.
The a. interossea anterior is often comparable in caliber to the radial artery (a. radialis) and participates in collateral circulation when major arteries of the forearm, including the posterior interosseous artery, are injured or ligated.