Assess & Address: Tarsal Tunnel Syndrome by Whitney Lowe

Anatomical background Pathology Assessment & Evaluation Treatment Massage Techniques

Anatomical background
A thorough understanding of TTS requires a brief review of anatomical structures in the region. The tibial nerve (also sometimes called the posterior tibial nerve) courses through the lower leg in the deep posterior compartment. As it exits it passes around the medial side of the ankle on its way to termination in the toes. Near the medial malleolus the tibial nerve divides into three branches (Figure 1). The medial calcaneal nerve is primarily a sensory branch that serves the posterior and bottom surface of the heel. The two other branches, the medial and lateral plantar nerves, carry motor and sensory signals to the plantar surface of the foot and into the toes.

Just after the tibial nerve divides into these three branches they all pass underneath a fascial band on the medial side of the ankle called the flexor retinaculum (also called the laciniate ligament, Figure 2). It is connected superiorly to the medial malleolus and inferiorly to the medial side of the calcaneus. The space underneath the flexor retinaculum is the tarsal tunnel. Note that there are anatomical variations to where the tibial nerve divides. As you can see in Figure 2, there are a number of other structures that pass through the tarsal tunnel as well. They include: the tendons of tibialis posterior, flexor digitorum longus, flexor hallucis longus, the posterior tibial artery and posterior tibial veins.

Sometimes the division of the tibial nerve occurs after the nerve exits the tarsal tunnel instead of before entering it. Consequently, descriptions of structures within the tarsal tunnel usually list only the tibial nerve instead of each of the three branches. In this article, the tibial nerve is listed as the involved nerve. However, keep in mind any of the branches may be separately affected depending on the client’s unique anatomical configuration. In fact, branching of the tibial nerve inside the tunnel or prior to entering it increases the likelihood of symptoms occurring from nerve pathologies.