The sinus tarsi is a space filled by the extensor digitorum brevis muscle and its fat pad that lies between the lateral aspects of the talus and calcaneus. It may be palpated directly below the anterior talofibular ligament.


Tenderness upon palpation and focal pain over the sinus tarsi is referred to as sinus tarsi syndrome and is caused by chronic synovitis, arthritis, or injury of the posterior portion of the subtalar joint.