Superior fibular tunnel

The superior fibular tunnel (Superior peroneal tunnel) is the anatomical compartment located behind the lateral malleolus of the fibula through which the peroneal (fibular) tendons pass.

Boundaries and Structure

• Roof: The superior peroneal retinaculum (SPR), a fibrous band that spans from the posterolateral ridge of the fibula to the lateral surface of the calcaneus.

• Floor: Composed of two components:

  • An osseous component: the retromalleolar groove (fibular groove) on the posterior surface of the lateral malleolus.

  • A non-osseous component: the lower part of the posterior intermuscular septum of the leg.

Contents: The tunnel normally contains the tendons of the fibularis longus and fibularis brevis muscles

Clinical Significance

The superior peroneal tunnel is clinically important because its anatomy directly relates to the causation of peroneal tendinopathies, including peroneal tendon subluxation and dislocation. The retromalleolar groove was found to have a consistently concave contour and forms only part of the tunnel floor, suggesting it is an unlikely primary cause of tendinopathies in isolation. Rather, the presence of additional structures within the tunnel, insufficiency of the superior peroneal retinaculum, or anatomic variants may contribute to peroneal tendon pathology.

Note: the superior fibular tunnel should be distinguished from the fibular tunnel at the proximal fibula (around the fibular head and neck), which is a musculoaponeurotic tunnel through which the common peroneal (fibular) nerve passes and where it is susceptible to compression.