![nail matrix nail matrix](https://deansmithmd.com/img/nail-bed-anatomy.jpg)
It has long rete ridges whose tips point distally. Histologically, the nail matrix has a relatively thick stratified squamous epithelium that lacks a granular layer. The contour of the distal margin of the nail plate follows the shape of the lunula as seen in neonates and following nail avulsion.
![nail matrix nail matrix](https://els-jbs-prod-cdn.jbs.elsevierhealth.com/cms/attachment/72338202-29a2-475b-a877-29142cc315d5/gr1.jpg)
The lunula is most prominent on the thumb and gets concealed by the PNF as one progresses to the digits on the ulnar side. When its distal end extends past the PNF, an opaque half-moon shape can be seen, which is the lunula. Its proximal end resides halfway between the distal interphalangeal (DIP) joint and the PNF. The nail matrix is the origin of the nail plate. Additionally, onychocytes are flatter and do not desquamate like corneocytes. Contrary to the stratum corneum, the nail plate has a lower percentage of total fat and water, a more significant percentage of cysteine, and thus, many strong disulfide bonds. Like the stratum corneum, the nail plate contains keratinocytes that have lost their nuclei, which contributes to the translucency of the nail plate. Histologically, the nail plate resembles a modified stratum corneum. The curvature of the nail plate along both the transverse and longitudinal axes contributes to its strength and allows for a snug fit within the proximal nail fold (PNF) and lateral nail folds (LNFs). It is a rigid, keratinized structure composed of around 196 rows of compact, well-differentiated keratinocytes that are called onychocytes. This section explains the anatomy of the nail unit and histologic findings of each region.
![nail matrix nail matrix](https://www.ncbi.nlm.nih.gov/books/NBK482237/bin/NailBiopsyTypeB-01.jpg)
The nail unit includes the nail plate and supporting structures.