A Split Above: Case Report on High Bifurcation of the Tibial Nerve

Abstract

The tibial nerve, one of the terminal branches of the sciatic nerve, is a mixed nerve that provides motor innervation to the posterior leg and most intrinsic foot muscles, and cutaneous innervation to the plantar surface of the foot. Here we report a case of an 84 year-old female donor with a tibial nerve bifurcation more proximal to the medial malleolar-calcaneal axis that, to our knowledge, has ever been reported before in the literature. Routine donor dissection conducted at the University of Maryland Eastern Shore Department of Physical Therapy found that the tibial nerve divided into medial and lateral plantar nerves deep to the soleus muscle in the posterior compartment of the leg. The medial malleolar-calcaneal axis was used as a reference line for measurements, spanning from the medial malleolus to the medial calcaneal tubercle. Measurements were taken with a Kynup digital caliper and the split was found to occur 158.06 mm proximal to the medial malleolar-calcaneal axis. Understanding the extent of neurovascular variation in the medial ankle is critical as this region is commonly targeted in medical interventions such as a nerve block or pin and plate placement for fracture fixation. Here we expand the current knowledge of anatomical variation possible in the human body highlighting the need for imaging during patient specific medical interventions.