Variations in the origin of the medial calcaneal nerve.

Previous anatomic studies of the medial heel region were done on embalmed human cadavers. Here, the innervation of the medial heel region was studied by dissecting living tissue with the use of 3.5-power loupe magnification during decompression of the medial ankle for tarsal tunnel syndrome in 85 feet. The medial heel was found to be innervated by just one medial calcaneal nerve in 37% of the feet, by two medial calcaneal nerves in 41%, by three medial calcaneal nerves in 19%, and by four medial calcaneal nerves in 3%. 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, where it is at risk for injury during calcaneal spur removal or plantar fasciotomy. Knowledge of the variations in location of the medial calcaneal nerves may prevent neuroma formation during surgery and provide insight into the variability of heel symptoms associated with tarsal tunnel syndrome.