The normal healthy fingernail is composed of laminated layers of keratin. It is composed of several parts:
- Nail root (germinal matrix) is the portion of the nail that actually sits beneath the skin behind the fingernail and extends several millimeters into the nail. The lunula is the whitish, half-moon shape at the base of the nail underneath the plate.
- Nail bed is part of the nail matrix also know as the sterile matrix. It is the skin upon which the nail plate sets. Cells at the base of the nail bed (matrix) produce the fingernail plate. As the nail is produced by the root, it streams down along the nail bed, which adds material to the undersurface of the nail making it thicker. It is important for normal nail growth that the nail bed be smooth. If it is not, the nail may split or develop grooves that can be cosmetically unappealing. Nails grow approximately 0.1 mm a day. It takes a fingernail about 4-6 months to fully regenerate.
- Nail plate is the hard portion of your nail that is most visible (the actual fingernail) and is made of translucent keratin. The pink appearance of the nail comes from the blood vessels underneath the nail.
- Eponychium (cuticle) is the thin layer of skin overlying the base of the nail. It helps protect the new keratin cells that emerge from the nail bed. It is situated between the skin of the finger and the nail plate fusing these structures together and providing a waterproof barrier.
- Perionychium is the skin overlying the nail plate on its sides. It is the site of hangnails and the infection paronychia.
- Hyponychium is the area between the nail plate and the fingertip. It is the junction between the free edge of the nail and the skin of the fingertip and like the epinychium provides a water-proof barrier.
Other nail conditions indicate disease.
Beau's Lines are indentations that run across your nail. They appear when growth at the matrix is interrupted. This may occur because of an injury or severe illness, such as a heart attack or malnutrition.
Clubbing results from low oxygen levels in your blood and often is a sign of lung disease. It may also be associated with inflammatory bowel disease or liver disease.
Onycholysis is a condition in which the nail separates from the nail bed. It is associated with injury, thyroid disease, fungal disease, drug reactions, psoriasis, and reactions to nail hardeners or acrylic nails.
Pitting of the fingernail is associated with conditions that can damage your nail's cuticle, such as chronic dermatitis, alopecia areata, or psoriasis.
Spoon nails (koilonychia) are nails that are soft and look scooped out. The depression is usually large enough to hold a drop of liquid. They may be a sign of iron deficiency anemia.
Terry's nails is a condition in which the nail looks opaque, but the tip has a dark band. It may be attributed to aging or a sign of serious illness, such as congestive heart failure, diabetes, liver disease, or malnutrition.
Yellow or green discoloration of the fingernail may result from a respiratory condition, such as chronic bronchitis or emphysema. It may also result from chronic swelling of your hands (lymphedema).
Care Tips for Healthy Nails:
- Don't abuse your nails. Your fingernails are not "tools". They are not meant to be used as screwdrivers. Use the appropriate tool.
- Don't bite your nails or pick at your cuticles. These habits can damage the nail bed and introduce bacteria from your mouth or environment (fungus) into the injuried skin/nail matrix and cause an infection (paronychia). Because your nails grow slowly, an injured nail retains signs of an injury for several months.
- Protect your nails. Wear cotton-lined rubber gloves when using soap and water for prolonged periods or when using harsh chemicals. This also protects your skin from the chemicals.
- Perform routine nail maintenance. Trim fingernails and clean under the nails regularly. Use a sharp manicure scissors or clippers and an emery board to smooth nail edges. Never pull off hangnails — doing so almost always results in ripping living tissue. Instead clip hangnails off, leaving a slight angle outward. Don't share nail files or clippers as this can spread infection.
- Moisturize your nails frequently. Nails need moisture just like your skin does. Rub lotion into your nails when moisturizing your hands. Be sure to apply a moisturizer each time you wash your hands.
- If you have regular manicures, don't have your cuticles removed as it can lead to nail infection. Make sure that your nail technician properly sterilizes all the tools used during your manicure. Unsterilized tools may transmit viral infections, such as hepatitis B or warts.