Posterior Interosseous Forearm Space

spatium posterior antebrachii interosseum

The posterior interosseous forearm space lies between the superficial and deep extensor muscle layers in the posterior forearm, containing the posterior interosseous nerve, posterior interosseous artery, and the muscular branches to the deep extensor compartment.

Region: Forearm

Clinical Relevance

Clinical Notes

The posterior interosseous forearm space is accessed in the posterior approach to the radius (Thompson approach) and during posterior interosseous nerve exploration. The extensor digitorum communis and ECRL/ECRB are the superficial layer retracted to expose this space. It is relevant in compartment syndrome of the posterior forearm compartment and in deep forearm extensor laceration repair.

Pathology

Common Injuries & Conditions

Posterior Forearm Compartment Syndrome

Pressure elevation in the posterior interosseous forearm space from crush injury or bleeding, producing finger extension weakness and posterior forearm pain on passive finger flexion, requiring posterior forearm fasciotomy.