Tarsal Tunnel Syndrome: An Ultrasound Pictorial Review

Abstract

Tarsal tunnel syndrome may be idiopathic or may be caused by various conditions: bone disease, thickening of the retinaculum, hematoma, or iatrogenic nerve damage; tendinopathy or tenosynovitis; the presence of supernumerary muscles such as an accessory soleus, peroneocalcaneus internus, or accessory flexor digitorum muscle; bone or joint disorders; expansile tumors or cysts; and venous aneurysm or kinking of the tibial artery. The purpose of this article is to describe and illustrate most of the causes of tarsal tunnel syndrome, as diagnosed by ultrasound, which is a practical, inexpensive method.

EURO-MUSCULUS/USPRM Dynamic Ultrasound Protocols for Ankle/Foot

“…This syndrome refers to the entrapment of the main trunk of the tibial nerve and/or its divisional branches (medial/lateral plantar nerve and inferior calcaneal nerve) at the medial aspect of the ankle 14 . A variety of space-occupying lesions, such as flexor tenosynovitis, ganglia, lipomas, engorgement of the posterior tibial veins, fascial septae, anomalous tendon/muscle (eg, flexor digitorum accessorius longus), or bony irregularities, may compress the nerve (Fig.…”

Sonographic assessment of the tarsal tunnel compared to cadaveric findings: a pictorial study

“…In the distal TT segment, TN divides into its terminal branches. Based on the division of TN, the TT may be divided into a proximal TT, containing TN, and a distal TT, containing the terminal branches of TN ( 3 , 7 ) .…”

“…Posterior to the two tendons, the terminal branches of TN can be observed: MPN running anteromedially and LPN running postero-laterally, both with accompanying terminal branches of PTA and PTV ( Fig. 2 ) ( 3 , 11 ) . BN can be visualized posterior to LPN.…”

“…TN has three terminal branches: MPN, LPN and MCN ( 1 – 3 , 5 , 7 , 13 , 16 ) . The fourth branch, BN, usually branches from LPN.…”

“…When MCN bifurcates above the level of the flexor retinaculum, it can run superficially and does not necessarily enter the TT ( 9 , 15 ) . Due to its small size, MCN is difficult to visualize on ultrasound ( 3 , 16 ) . We were unable to locate MCN during our ultrasound examination.…”