interosseum

Interosseum is a term used in anatomy to denote the interosseous membrane or the space between two adjacent bones. The word derives from Latin, with inter- meaning between and os meaning bone. In common anatomical usage, the most familiar interosseous membranes are those between the forearm bones (radius and ulna) and between the leg bones (tibia and fibula).

In the forearm, the radioulnar interosseous membrane is a fibrous sheet that connects the radius and ulna along their lengths. It helps bind the two bones together, distributes load from the radius to the ulna during weight-bearing and grasping, and serves as a site for muscle and fascial attachments. The membrane also contributes to the forearm’s stability and to the mechanical separation of the anterior and posterior compartments, aiding rotational movements.

In the leg, the tibiofibular interosseous membrane similarly spans the shafts of the tibia and fibula, stabilizing the distal tibiofibular joint and transmitting forces between the bones during locomotion. It supports the overall integrity of the leg’s limb segments and influences ankle mechanics.

Clinical relevance centers on injury to the interosseous membrane. Tears or disruptions can accompany fractures of the forearm or leg bones and may lead to instability, impaired load transmission, and chronic pain. In the forearm, syndesmotic injuries and Essex-Lopresti injuries involve interosseous membrane damage and have implications for forearm and wrist function.

See also: interosseous membrane, syndesmosis, interossei muscles.

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