Fascia · Lower leg

Transverse intermuscular septum

A sheet lying across the back of the calf that separates the muscles you can feel from the ones you cannot. Behind it are the bulky gastrocnemius and soleus; in front of it, hugging the bones, lie tibialis posterior and the long toe flexors. It stretches from the medial border of the tibia across to the fibula, closing the deep posterior compartment off as a distinct space. The posterior tibial artery and the tibial nerve run the length of the leg on its deep side, which is why neither can be felt through the calf.