skin biopsy
 

My skin biopsy was taken from 10 cm above my right heel.

Usually they do epidermal nerve fiber biopsies at 4 sites, at the heel, calf just below the knee, upper inner thigh and forearm.

A sural nerve biopsy which has fallen out of favor is performed at the heel. A sural nerve biopsy damage a larger nerve, so many docs opt for skin biopsy instead.