Fascia · Ankle

Superior peroneal retinaculum

Retinaculum musculorum fibularium superius

A short strap behind the bony bump on the outside of the ankle, running from the back border of the lateral malleolus down onto the outer surface of the heel bone. The two fibularis (peroneal) tendons turn a sharp corner here, sitting in a shallow groove behind the bone, and this band is what holds them in it. It is not a separate ligament but a local thickening of the leg's fascial sleeve, blending above with that sleeve and below with the sheath of the tendons it covers. Because it is the only restraint at the corner, it is the structure that stops those tendons flicking forwards over the malleolus when the ankle is forced into a turn.