The interosseous membrane of the leg connects the tibia and fibula throughout the leg, transferring approximately 15 percent of axial leg load from the fibula to the tibia and providing attachment surfaces for the anterior, posterior, and lateral compartment muscles. It is disrupted in Maisonneuve fractures — proximal fibula fractures combined with disruption of the syndesmosis and interosseous membrane producing ankle instability from proximal fibula level injury.
| Origin | Lateral (interosseous) border of the tibia |
|---|---|
| Insertion | Medial (interosseous) border of the fibula |
| Actions | Transfers axial load from the fibula to the tibia; provides attachment for deep posterior and anterior compartment muscles; stabilises the tibiofibular relationship along the leg |
|---|
The Maisonneuve fracture pattern (proximal fibular fracture with syndesmotic disruption) must be recognised in all ankle injuries by examining the full fibula length when ankle films show no lateral malleolus fracture but medial ankle disruption is present. Syndesmotic fixation and potentially fibular fixation are required.
Proximal fibular fracture with interosseous membrane and syndesmotic disruption producing unstable ankle mortise requiring syndesmotic fixation despite no lateral malleolus fracture.
