ABSTRACT
INTRODUCTION Evolving from the primeval claw, the nail's working uses became less important, while over time their aesthetic value has grown in importance. The application of cosmetics to the nail can is done to enhance length, beautify or address speci‘c needs. The nail is a convex, hard, horny plate covering the dorsal aspect of the tips of the ‘ngers and toes (Figure 30.1). Its appearance is determined by the integrity of the terminal bony phalanx and the paronychium, and i.e. matrix, nail bed and hyponychium, and nail folds. The nail plate, produced by the matrix, grows from a pocket-like invagination of the epidermis and adheres ‘rmly to the nail bed. Tissue from the undersurface of the proximal nail fold also tightly adheres to the surface of the nail and as the nail grows, emerges from underneath the eponychium to create the cuticle. This cuticle tissue creates a resistant gasket-like seal which helps protect the nail pocket from infection, irritants, etc. The most distal part of the matrix, the whitish semicircular lunula, is visible wherever it extends beyond the proximal nail fold. Juxtaposed to the lunula, the pink nail bed epithelium is made from parallel longitudinal rete ridges and subepithelial capillaries running longitudinally at different levels. Adjacent to the nail bed, the hyponychium, an extension of the epidermis under the nail plate, marks the point at which the nail separates from the underlying bed tissue. There is small area between the nail and the distal bony phalanx that is occupied by non-keratinizing nail epithelium, as well as highly vascular mesenchyme containing glomus organs.
