Extensor tendoscopy of the ankle.

The extensor digitorum longus muscle (EDL) arises from the upper three-quarters of the extensor surface of the fibula, the interosseous septum and from a small area of the tibia across the superior tibiofibular joint. It forms its four tendons which are restrained by the superior and inferior extensor retinacula. The two retinacula prevent the EDL and extensor hallucis longus (EHL) tendons from bow stringing. The inferior extensor retinaculum also contributes to the stability of the subtalar joint. Extensor tendoscopy has been performed in 3 patients and no neural injury was noted.