Tarsal tunnel syndrome associated with a pulsating artery: effectiveness of high-resolution ultrasound in diagnosing tarsal tunnel syndrome.

We describe a patient with tarsal tunnel syndrome in whom ultrasound imaging revealed compression of the posterior tibial nerve by a pulsating artery. High-resolution ultrasound showed a round pulsating hypoechoic lesion in contact with the posterior tibial nerve. Ultrasound-guided injection of 0.5% lidocaine temporarily resolved the paresthesia. These findings suggest an arterial etiology of tarsal tunnel syndrome.