Chapter 1 7 Each cuticle cell is very thin (ca. 0.5 µm) compared with its lateral dimensions (50-60 µm) and is separated from its neighbors by a 250 Å-thick cell membrane complex (CMC). At this point it is important to emphasize that the CMC, in terms of both internal structure and chemistry, is not the same as the membranes of living cells. Rather, in the fully formed hair, it occupies the region occupied by the original follicular cell membranes with superficially similar structure to that of the original membranes but with dramatically altered chemical composition. The cuticle cells, similar to the outer longitudinal surfaces of the hair, are oriented at approximately five degrees to the fiber’s long axis. Such geometry conspires to put the distal edge of each cuticle cell sheet at the hair surface, whilst its proximal edge is, in a root wise direction, adjacent to the hair cortex. Even despite its thinness, each cuticle cell is internally laminated into a series of components with details as follows. Figure 4. Transmission electron micrograph of a transverse section through human hair cuticle showing the nomenclature for its sub-components. The section was stained with ammoniacal silver nitrate.