(A) Confocal image of a skin biopsy taken from the finger of a healthy subject illustrating different subtypes of sensory fibre: PGP 9.5 is used as an axonal marker (red) and myelin basic protein as a marker for myelin (green). (A) Confocal image of a skin biopsy taken from the finger of a healthy subject illustrating different subtypes of sensory fibre: PGP 9.5 is used as an axonal marker (red) and myelin basic protein as a marker for myelin (green). There are numerous free nerve endings entering the epidermis (white arrows) and a single myelinated fibre is innervating a Meissner's corpuscle (yellow arrow). (B) Electron micrograph of the sural nerve. The blue arrow shows a large diameter myelinated fibre, the purple arrow marks a small diameter myelinated fibre and the red arrow marks a Remak bundle in which one non-myelinating Schwann cell associates with multiple unmyelinated C-fibres which are ensheathed in Schwann cell pockets. Andreas C Themistocleous et al. Pract Neurol doi:10.1136/practneurol-2013-000758 ©2014 by BMJ Publishing Group Ltd