Fascia · Ankle

Inferior peroneal retinaculum

Retinaculum musculorum fibularium inferius

The lower of the two straps holding the fibularis tendons around the outside of the ankle, attached to the lateral surface of the heel bone in front of and behind a small bony shelf called the fibular trochlea. A septum drops from its deep surface onto that shelf, so the two tendons run in separate tunnels: fibularis brevis above the trochlea, fibularis longus below it, just before the longus turns under the foot. Above, its fibres run straight into the inferior extensor retinaculum, making the two a single continuous band around the front and outer side of the ankle. It is the restraint that holds those tendons down while they change direction twice in the space of a few centimetres.