The peroneal retinacula (singular: peroneal retinaculum) are fibrous bands which bind down the tendons of the Peronæi longus and brevis as they run across the lateral side of the ankle

Ankle

The ankle joint is formed where the foot and the leg meet. The ankle, or talocrural joint, is a synovial hinge joint that connects the distal ends of the tibia and fibula in the lower limb with the proximal end of the talus bone in the foot...

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The fibers of the superior retinaculum (external annular ligament) are attached above to the lateral malleolus and below to the lateral surface of the calcaneus.

The fibers of the inferior retinaculum are continuous in front with those of the cruciate crural ligament

Cruciate crural ligament

The inferior extensor retinaculum of the foot is a Y-shaped band placed in front of the ankle-joint, the stem of the Y being attached laterally to the upper surface of the calcaneus, in front of the depression for the interosseous talocalcanean ligament; it is directed medialward as a double...

; behind they are attached to the lateral surface of the calcaneus; some of the fibers are fixed to the peroneal trochlea

Peroneal trochlea

The Peroneal trochlea is a projection from the lateral side of the calcaneus between the tendons of the peroneus longus and brevis. Also known as fibular trochlea.-References:* http://www.medilexicon.com/medicaldictionary.php?t=94123...

, forming a septum between the tendons of the Peronæi longus and brevis.