Anatomy of a healthy fingernail

Anatomy of a healthy fingernail

This illustration shows components of a healthy fingernail.

---

Your nails are composed of laminated layers of a protein called keratin, which is also found in your hair and skin. Each nail comprises several parts, including the:

• Nail plate. The nail plate is the part of your nail that's most visible - the hard portion you see when you look at your fingernail.
• Nail folds. This is skin that frames each of your nail plates on three sides.
• Nail bed. Your nail bed is the skin beneath the nail plate. Cells at the base of your nail bed produce the fingernail or toenail plate and are responsible for holding on to the nail plate.
• Cuticle. Your cuticle is the tissue that overlaps your nail plate at the base of your nail. It protects the new keratin cells that slowly emerge from the nail bed.
• Lunula. The lunula is the whitish, half-moon shape at the base of your nail underneath the plate.

Your nails grow from the area under your cuticle (matrix), located at the base of the nail. As new cells grow, older cells become hard and compacted and are eventually pushed out toward your fingertips. Nails grow about 0.1 millimeter a day, which means that it takes a fingernail about four to six months to fully regenerate. Toenails may grow at a slightly slower rate. Healthy nails are smooth, without ridges or grooves. They're uniform in color and consistency and free of spots or discoloration.

Common nail conditions: Reading the signs

Some nail conditions are harmless. These include vertical ridges, which may become more pronounced as you age, and white lines or spots. Spots usually result from injury to the nail plate or nail bed. In time the white spots will grow out.

Other nail conditions can indicate disease. For example, yellow discoloration in your nails may result from a respiratory condition, such as chronic bronchitis, or from swelling of your hands (lymphedema) or from yeast or bacterial infection beneath the nail. If your nail pulls away from the nail bed, it could indicate psoriasis or intolerance to certain medications. Indentations that run across your nails, called Beau's lines, appear when growth at the area under your cuticle is interrupted. This might occur because of an injury or severe illness.

If you have a nail problem that persists or is associated with other signs and symptoms, make an appointment with your doctor to get it checked out. The doctor's visit typically includes an examination of your nails along with other observations and tests to make a diagnosis.

Vertical nail ridges, which run from the cuticle to the tip of the nail, are fairly common. These ridges typically become more prominent with age. Vertical ridging doesn't indicate serious illness.