The gross anatomy of human finger nail consists of the following:
1. Nail plate:
The nail plate is mainly produced by the matrix which emerges via the proximal nail fold and is held in place by the lateral nail folds. It overlays the nail bed and detaches from the latter at the hyponychium which is the skin under the free edge of the plate. The nail plate has an average thickness of 0.25–0.6 mm. It is hard, yet slightly elastic, translucent, convex and is made up of approximately 25 layers of dead, keratinised, flattened cells which are tightly bound to one another via numerous membrane coating granules, intercellular links and desmosomes (cell structure specialized for cell-to-cell adhesion). Chemically, the nail plate consists mainly of the…show more content… Hyponychium:
It is the epithelium located beneath the nail plate at the junction between the free edge and the skin of the fingertip. It forms a seal that protects the nail bed. (Debjit Bhowmik et al, 2013)
9. Onychodermal band:
It is the seal between the nail plate and the hyponychium and is found just under the free edge, in that portion of the nail where the nail bed ends and can be recognized by its glassy, greyish colour (in fair-skinned people). It is not perceptible in some individuals while it is highly prominent in others.
It is the small band of epithelium that extends from the posterior nail wall onto the base of the nail. Often and erroneously called the cuticle, the eponychium is the end of the proximal fold that folds back upon itself to shed an epidermal layer of skin onto the newly formed nail plate. This layer of non-living, almost invisible skin rides out on the surface of the nail plate. The eponychium forms a protective seal on the lateral edges of the nail plate.
It is the projecting edge of the eponychium covering the proximal strip of the lunula.
12. Nail wall:
Nail wall also called as Vallum unguis is the cutaneous fold overlapping the sides and proximal end of the