Ligament · Lower leg

Interosseous membrane of the leg

Membrana interossea cruris

A tough sheet strung between the facing borders of the shin bone and the fibula, filling the length of the gap between them. Its fibres run downward and outward from the tibia to the fibula, so load arriving on the tibia is partly handed across to the slimmer bone beside it. It is also a wall: it divides the leg into front and back compartments and gives extra origin surface to muscles on both faces. Two gaps interrupt it — a large one at the top, through which the anterior tibial artery passes forward into the front of the leg, and a small one near the ankle for the perforating branch of the fibular artery.