Superior peroneal retinaculum
The superior peroneal retinaculum is one of two fibrous bands that bind the peroneus longus and peroneus brevis muscle tendons that run over the ankle's lateral side. While these muscles stabilize the lateral ankle and evert the foot, the superior peroneal retinaculum creates a fibroosseous tunnel from the retromalleolar groove, working to prevent peroneal subluxation. The superior peroneal retinaculum is also known as the external annular ligament. Its fibers are connected to the lateral malleolus, above it, and the calcaneus's lateral surface, below it. Superior peroneal retinaculum injuries, as well as diseases such as tenosynovitis, can cause pain and instability in the lateral ankle. Injuries to the superior peroneal retina are measured by Oden's classification system. In their acute phase, injuries to this band are often mistaken for peroneal tendon abnormalities or ligamentous injuries. Fortunately, such conditions can be corrected by reconstructive surgery, which directly repairs the ankle's superior peroneal retinaculum; however, this is difficult in patients with insufficient structural remnants.
Written and medically reviewed by the Healthline Editorial Team
In Depth: Superior peroneal retinaculum