Innervation of the sinus tarsi and implications for treating anterolateral ankle pain.

Abstract

Anterolateral ankle pain can persist despite the best care of sprains or fractures. It is possible that this pain is related to stretch or traction injuries to the nerves that innervate the subtalar joint. If this were true, identification of these nerve branches by local anesthetic block would provide an indication that surgical interruption of the function of these nerves may provide pain relief. In 28 feet of 14 cadavers (7 male/7 female), investigation of the deep peroneal nerve demonstrated a consistent pattern whereby a series of 2 to 4 (mean, 2.9 +/- 0.6) branches innervated the anterolateral part of the subtalar joint. All these nerve branches originated from the lateral terminal branch of the deep peroneal nerve on the dorsum of the foot. The mean distance between the exit of the first articular branch and the exit of the terminal motor branch both originating from the lateral terminal branch was 3.8 +/- 1.1 cm. The motor branch passed under the extensor digitorum brevis muscle at a mean distance of 5.3 +/- 0.6 cm from the tip of the lateral malleolus. The presented anatomy provides a basis for the diagnosis and treatment of persistent anterolateral ankle pain of neural origin.