Tarsal tunnel syndrome is a result of tibial nerve compression or damage at the tarsal tunnel.
The tarsal tunnel is a passage in the medial ankle. It is bounded by the flexor retinaculum of the ankle, the medial malleolus of the tibia and the talus and calcaneus bones. Several structures pass through the tarsal tunnel including the tibial nerve, the posterior tibial veins, the posterior tibial artery, the tendon of the flexor digitorum longus, the tendon of the tibialis posterior muscle and the tendon of the flexor hallucis longus.
The tibial nerve is a branch of the sciatic nerve. It runs behind the femur, down through the popliteal fossa into the posterior compartment of the leg. As it reaches the ankle, it passes through the tarsal tunnel. Specifically, it passes under the flexor retinaculum of the ankle as it curves under the medial malleolus onto the medial surface of the foot. Here, it bifurcates into the medial and lateral plantar nerves. The tibial nerve supplies motor and sensory innervation to the muscles and skin of the posterior compartment of the leg and the plantar aspect of the foot.
When the tibial nerve is compressed or damaged at the tarsal tunnel, it can cause pain, numbness, tingling, burning and weakness in the affected foot.
There are many causes of tibial nerve damage. For instance, the shape of the foot can be a risk factor. Specifically, a flat foot or high arch can compress the tibial nerve. Injuries to the foot or ankle as well as growths such as bone spurs, ganglion cysts or varicose veins can also cause tarsal tunnel syndrome. Systemic diseases such as arthritis, diabetes or hypothyroidism can cause swelling in the body which can compress the tibial nerve.
Treatments for tarsal tunnel syndrome includes resting, elevating and icing the affected foot. Casts or splints can also be worn to help the healing process. Physical therapy exercises and orthotics can help in the long term and for prevention.
Check out Complete Anatomy to learn more about the tarsal tunnel and tibial nerve!
