[TA] broad thickened band of deep fascia overlying fibularis longus and brevis tendons as they pass along the lateral margin of the foot, anchoring the tendons and their associated bursae in place; it is a lateral continuation of the stem of the Y-shaped inferior extensor retinaculum that attaches to the fibular trochlea of the calcaneus, which intervenes between the two tendons, and then continues to attach to the inferolateral aspect of the calcaneous. SYN: retinaculum musculorum fibularium inferius [TA], inferior peroneal retinaculum*, retinaculum musculorum peroneorum inferius*.