Variations in the origin of the medial and inferior calcaneal nerves.
INTRODUCTION: Entrapment of the medial heel region nerves is often mentioned as a possible cause of heel pain. Some authors have suggested that the medial and inferior calcaneal nerves may be involved in such heel pain, including plantar fasciitis, heel pain syndrome and fat pad disorders. The aim of this study was to give a detailed description of the medial heel that would determine the variability and pattern of the medial and inferior calcaneal nerves, as well as to relate these findings to the currently used incision line for tarsal tunnel, fixations of fractures with external nailing, medial displacement osteotomy and nerve blocks in podiatric medicine. MATERIALS AND METHODS: The origin, relationship, distribution, variability and innervation of medial and inferior calcaneal nerves were studied with the use of a 3.5 power loupe magnification for dissection of 25 adult male feet of formalin-fixed cadavers. The medial heel was found to be innervated by just one medial calcaneal nerve in 38% of the feet, by two medial calcaneal nerves in 46%, by three medial calcaneal nerves in 12% and by four medial calcaneal nerves in 4%. An origin for a medial calcaneal nerve from the medial plantar nerve was found in 46% of the feet. This nerve most often innervates the skin of the posteromedial arch. RESULTS: In our dissection, the rate of occurrence of the medial and inferior calcaneal nerves in medial heel region was 100%. When compared with the inferior calcaneal nerve, the medial calcaneal nerve was posterior, superior and thicker. The inferior calcaneal nerve supplies deeper structures. In the majority of the cases, inferior calcaneal nerve aroused from the lateral plantar nerve, but it may also arise from the tibial nerve, sometimes in a common origin with the medial calcaneal nerve. CONCLUSIONS: Knowledge of fine anatomy of the calcaneal nerves is necessary to ensure safe surgical intervention in the medial heel region.