The interosseous membrane of the leg is also referred to as the middle tibiofibular ligament. This ligament extends through the fibula and tibia's interosseous crests and separates the muscles in the back of the leg from the muscles located in the front of the leg.
It is made of an aponeurotic lamina, which is a thin layer of oblique, tendon-like fibers. Most of the fibers run laterally and downwards while the others run in an opposite direction.
The ligament thins out at the lower portion, but is broader in the upper half. The upper portion of the interosseous membrane of leg does not reach the tibiofibular joint, but does create a large concave border that allows the anterior tibial vessels to pass through to the front of the leg. On the lower part of the interosseous membrane of leg there is an opening so that the anterior peroneal vessels can pass through. In addition to the two main openings for the passage of vessels, there are also numerous openings so that small vessels can pass through.