The posterior tibial nerve is a portion of the sciatic nerve that runs down the posterior leg into the foot. It can be entrapped at two major sites: behind the knee at the proximal edge of the soleus muscle and at the ankle in the tarsal tunnel. The small terminal branches of the tibial nerve can be entrapped in the distal ankle and foot and are discussed in other chapters. Posterior tibial nerve entrapment can lead to pain and dysesthesias in the calf and sole of the foot, as well as dysfunction of the foot flexors and intrinsic muscles.