The extensor retinaculum of the ankle consists of a superior band between the tibia and fibula and an inferior Y-shaped band from the lateral calcaneus to the medial ankle structures. Together they hold the extensor tendons in their compartments as they cross the ankle, preventing the tendons from bowstringing away from the bone during dorsiflexion. Anterior tarsal tunnel syndrome occurs when the deep peroneal nerve is compressed under the inferior extensor retinaculum.
| Origin | Superior retinaculum: anterior tibia and fibula. Inferior retinaculum: lateral calcaneus (lateral stem, Y-shape) |
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| Insertion | Superior: medial malleolus. Inferior: medial cuneiform and plantar fascia (deep limb), and navicular and medial malleolus (superficial limb) |
| Actions | Constrains the anterior ankle tendons in their compartments during dorsiflexion; prevents bowstringing of the tendons across the ankle joint |
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Anterior tarsal tunnel syndrome from inferior extensor retinaculum compression of the deep peroneal nerve produces dorsal foot numbness in the first web space and EDB weakness without ankle dorsiflexion weakness. It is reproduced by foot dorsiflexion against resistance and relieved by retinaculum release. Extensor retinaculum tenosynovitis from shoe lace pressure produces dorsal ankle pain managed with padding and lace adjustment.
Deep peroneal nerve compression under the inferior extensor retinaculum producing first web space numbness without ankle dorsiflexion weakness, managed with retinaculum release.
