Sinus tarsi syndrome

1. What is the sinus tarsi?
2. What is the mechanism of sinus tarsi syndrome?
3. What is seen clinically in sinus tarsi syndrome?
4. What is the treatment of sinus tarsi syndrome?

Answers:
1. A small osseous canal which runs into the ankle under the talus bone.
2. Excessive foot pronation causing adduction of the talus, often with h/o arthritis or prior ankle injury.
3. Pain on the anterolateral aspect of the foot/ankle over the sinus tarsi, which resolves with injection of local anesthetic into the sinus tarsi.
4. Conservative treatment is the same as for ankle sprain, surgical treatment includes decompression of the tunnel.