Staining of cutaneous nerves across three sites on the sole of the foot using Sihler’s method. Nerve fibers were stained in abundance across all three sites; A – Forefoot, B – Arch, C – Heel. The epidermis in the heel was thicker than in the forefoot and arch. Thus, the identifiable nerves terminated deeper in the heel. The solid line in A-C is the skin surface, the dashed line is the dermo-epidermal junction, and the arrows indicate examples of cutaneous nerve fibers used for quantification. D– Approach used to quantify the number of nerve fibers. The # value indicates how many fibers were counted in each of the five examples. Nav1.7 immunoreactive nerve fibers were only counted inside the dermal papillary, the grey area in D, while nerves identified using Sihler’s staining were counted inside the dermis over a maximum distance of 1 mm from the dermo-epidermal junction. Scale bars represents 1 millimeter. SC: stratum corneum, Epi: Vital epidermis, Der: Dermis.
Frahm et al. BMC Neuroscience 2013 14:116 doi:10.1186/1471-2202-14-116