Nails often prompt questions about their biological nature, particularly whether they are composed of living or dead cells. Understanding their composition clarifies this common inquiry.
The Nature of Your Nails
The visible portion of your nail, known as the nail plate, is indeed made up of dead cells. These cells are primarily composed of a tough, fibrous protein called keratin. This same protein is also a main component of human hair and the outer layer of skin. Because the nail plate consists of cells that are no longer living, it does not contain nerves or blood vessels.
This absence of living cells, nerves, and blood supply explains why cutting the nail plate does not cause pain or bleeding. When you trim your nails, you are simply removing hardened, non-living material. However, the skin and tissues underneath and around the nail do contain nerves and blood vessels, which is why cutting too far back or injuring the surrounding area can be painful.
How Your Nails Grow
Nail growth originates from a specialized area located at the base of the nail, beneath the skin, called the nail matrix. Here, new, living cells are continuously produced. These cells multiply rapidly and then undergo a process called keratinization. During keratinization, the cells harden, flatten, and fill with keratin protein, losing their nuclei in the process.
As new cells form in the matrix, they push the older, keratinized cells forward and outward. This continuous action lengthens the visible nail plate. Fingernails typically grow at an average rate of about 3 to 3.5 millimeters per month, while toenails grow more slowly, at roughly 1 millimeter per month.
Understanding Nail Structure
The nail unit comprises several distinct parts, each contributing to its function and growth. The nail plate is the hard, translucent part that is most visible. It rests on the nail bed, soft tissue underneath containing blood vessels that give the nail its pinkish appearance.
At the base of the nail, a thin layer of skin called the cuticle (eponychium), forms a protective seal. This seal helps prevent bacteria and debris from entering the nail matrix. The lunula, Latin for “small moon,” is the whitish, crescent-shaped area often visible at the base of the nail, representing part of the nail matrix.
The Purpose of Nails
Human nails serve multiple biological functions beyond their cosmetic appearance. They protect sensitive fingertips and toes from trauma and safeguard underlying soft tissues and nerve endings.
Nails also enhance dexterity and the ability to perform delicate tasks. They provide counter-pressure on the pulp of the finger, which can increase the sensitivity of the fingertip for fine motor activities like picking up small objects or separating pages. Additionally, nails assist in actions like scratching or scraping.