[Sinus tarsi syndrome. MRI diagnosis]

Sinus tarsi syndrome is a well-defined clinical pathological entity. The sinus tarsi is an anatomic space between the inferior aspect of the talus and the superior aspect of the calcaneus, anterior to the posterior subtalar joint. The entire space is filled with fat, five ligaments and vessels. MRI demonstrates characteristic findings with obliteration of normal fat and lack of visualization of the ligaments. This syndrome is relatively frequent and is related to trauma in about 70% in association with the lateral collateral ligament and tibialis posterior tendon injuries. In the remaining 30% the reason is an inflammatory condition.