Understanding nails begins with knowing their structure. Aesthetic and wellness expert Dr. Rhoda Espino explains that nails, just like the hair, are composed mainly of hard keratin and collagen, which are proteins. The nail has different parts—each important to the nail’s overall health and appearance.
The nail root or germinal matrix lies beneath the skin behind the fingernail. It generates the nail tissue. On the edge of the nail root is the lunula, the white, crescent shape we see under the nail.
The nail bed, which extends from the edge of the nail root, contains blood vessels, nerves, and melanin-producing cells called melanocytes (melanin is the dark pigment of the skin). The nail bed is where the nail streams down from the root. It is important that the nail bed be kept smooth, otherwise it can cause nails to split or form grooves.
The nail plate is the actual nail. The surface underneath the nail plate has grooves that help anchor it to the nail bed. It is the blood vessels underneath the nail that provides its pink appearance.
The eponychium, cuticle, or nail fold is located between the skin of the finger and the nail plate. It serves as a waterproof barrier that protects the nail from contaminants and infection.
The perionychium is perhaps the “most commonly injured” part of the nail. It is the skin that overlies the nail plate on its side, and is the site of hangnails and ingrown nails.
If left untrimmed and unbroken, there’s a white area of the nail that grows past the fingertips. It is called the free edge. The junction between the free edge and the skin of the finger tip is the hyponychium.
Nails grow at the rate of about 0.05 to 1.2 mm per week but the growth rate slows down with age and poor blood circulation. Compared to toenails, fingernails grow faster at an average 3 mm per month. Generally, it takes six months for a fingernail to grow from the root to the free edge. On the other hand, toenails grow about 1 mm per month and may take a year and a half to grow out completely.