Sinus tarsi syndrome is a poorly understood term in the orthopedic world. It is thought of as a painful condition of the sinus tarsi that often responds to corticosteroid injection and is associated with a feeling of instability in the hindfoot. Despite references in the literature, there is no agreement on pathognomonic history, clinical tests, or imaging studies that could help in confirming the diagnosis or establishing the etiology. Some authors relate the clinical condition of sinus tarsi syndrome with instability of the subtalar joint.