Sinus tarsi syndrome steroid injection

The sinus tarsi is an anatomical tunnel (space) that starts outside the foot and continues deep within the foot. It is located between two bones within the back of the foot, the talus and calcaneum, just in front of the large bony bump at the outside of the ankle (called the lateral malleolus). The sinus tarsi provides stability to the hindfoot (joints at the back of the foot). It contains fatty tissue, small nerves and vessels.  The structures within the tarsal sinus can be injured secondary to repeated ankle sprains or if there are biomechanical abnormalities that would put extra stress on the area (like flatfoot of hypermobility).