Nail Structure Anatomy

Table of Contents

Nail structure

The nail is made up of four main components called the nail plate, nail folds, nail bed, and hyponychium.

Nail plate

Part of a fingernail structure is the nail plate, which is the hard nail that covers each finger tip or toe nail. It consists of keratinized, dead cells which are formed towards the end of the nail matrix in a region called the germinal matrix. The nail body consists of approximately one hundred layers in total, with only fifty in the visible part of the nail.

Nail plates are metabolically active mainly at their root where blood vessels are plentiful supplying nutrients needed to grow healthy nails. Uneven nail plates may result from nutritional deficiency due to decreased blood supply for example during cold weather when hands are frequently covered by gloves thereby limiting oxygen flow into blood vessels and nail growth.

Nail plates mature through a process of weeks/months ending up as physiologic leukonychia found at their tips during certain stages of development.  Therefore, nail plates are always composed of the nail bed’s older keratin.

Nail Matrix

The nail matrix is the nail’s source of nail cells, located at the base of each nail in a section called the nail root. It contains melanocytes, Merkel cells , sensory receptors and nail stem cells which reside underneath the nail matrix epithelium layer as seen on the picture to the right.

Photo by KARTIK GADA on Unsplash

Nail bed

The nail bed is a thin membrane beneath each nail plate from where it laterally grows forward pushing older keratinized material towards its free end, creating a space known as subungual region or sulcus that contain old nails and debris which accumulate there over time.

Nail folds

The nail folds (volar nail aspect) or skin creases (palmar nail aspect) are small folds of epidermal cells which form just distal to the nail matrix and nail bed enveloping them completely laterally and making up 95% of nail plate volume. Nail grooves guide them over their roots before reaching the free edge where they dissipate into nothingness.

Hyponychium

The hyponychium is a thin layer of non-cornified stratified squamous epithelium located at the free edge proximally thus making up 5% of nail plate volume as seen on picture below:

Your nails should be no more than 1mm thick for nail plates to properly grow nail folds. The nail plate serves as a protective shield preventing germs from reaching your nail bed and nail matrix, which are both very tender surfaces of your body located right beneath the nail plate.

Normal healthy nail should have an opaque, smooth surface showing regular light pink coloration on both its free edge proximally and cuticle distally. It should be firmly attached to the nail bed and nail folds with no visible spaces between. It should be made up of approximately one hundred nail layers, which is why you can see nail grooves at their free edge as nail plates mature from the root towards their tips.

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