Interosseous membrane of leg

At a glance

English

Interosseous membrane of leg

Latin (TA2)

Membrana interossea cruris

System

Ligament

Region

Lower limb

Side

Paired, left and right

About the interosseous membrane of leg

This membrane stretches across the gap between the two leg bones, attaching to the sharp interosseous border along the outer side of the tibia and the matching border on the inner side of the fibula. It forms a fibrous joint, or syndesmosis, along most of the length of the leg, and below it carries on without a break into the interosseous ligament of the distal tibiofibular joint.

The sheet is thin and tough, built of fibres that mostly run downwards and outwards from tibia to fibula, with a smaller number crossing the other way. It is wider at the top than at the bottom. Its upper edge does not quite reach the proximal tibiofibular joint; instead it ends in a free curved margin, above which a large oval gap lets the anterior tibial vessels pass from the back of the leg to the front. Near its lower end a smaller opening carries the perforating branch of the fibular artery forwards, and many tiny holes let small vessels through.

The membrane is a dividing wall and a muscle attachment. In front of it lie the extensor muscles (tibialis anterior, the long extensors of the toes and great toe, and fibularis tertius), with the anterior tibial vessels and the deep fibular nerve running down on its surface. Behind it lie flexor hallucis longus and tibialis posterior. Several of these muscles take part of their origin from the membrane itself.

It also binds the fibula to the tibia and helps share load between them. In a Maisonneuve injury, a twisting force at the ankle tears the distal syndesmosis and runs up the membrane to break the upper fibula, so the whole length must be checked. Because it closes off the anterior and posterior compartments of the leg, it is part of the tight envelope in which swelling can cause compartment syndrome.

Attachments and function

Attaches from

The interosseous border of the tibia.

Attaches to

The interosseous border of the fibula, and below it the interosseous ligament of the distal tibiofibular joint.

Function

Binds tibia and fibula, separates the anterior from the posterior compartment of the leg and gives origin to leg muscles.