Nail (anatomy)

Nail (anatomy)

A nail is a horn-like envelope covering the tips of the fingers and toes in most primates, including humans. Nails are similar to claws in other animals. Fingernails and toenails are made of a tough protective protein called keratin. This protein is also found in the hooves and horns of different animals.

Structure

Nails consist of several parts, including the nail plate, nail bed, cuticle, lunula, and matrix. The nail plate is the hard part of the nail, while the nail bed is the skin beneath the nail plate. The cuticle is the tissue that overlaps the plate and rims the base of the nail. The lunula is the visible part of the matrix, the whitish crescent-shaped base of the visible nail. The matrix, also known as the "matrix unguis," is the tissue (or germinal matrix) which the nail protects. It is the part of the nail bed that extends beneath the nail root and contains nerves, lymph, and blood vessels.

Function

Nails serve several purposes, including protecting the distal phalanx, the fingertip, and the surrounding soft tissues from injuries. They also enhance precise delicate movements of the distal digits through counter-pressure exerted on the pulp of the finger. Nails can also be an indicator of a person's general health, with various conditions affecting their appearance.

Growth

Nail growth is a complex process that occurs in the matrix. The average growth rate for nails is about 3 mm a month for fingernails and 1 mm a month for toenails. Factors such as age, sex, and season can affect the growth rate. Nails tend to grow faster in younger people, in males, and during the summer.

Clinical Significance

Nails can be affected by various conditions, including onychomycosis (fungal infection), paronychia (infection of the nail fold), and psoriasis (a skin condition that can affect the nails). Changes in nail appearance can also indicate systemic conditions such as anemia, diabetes, and thyroid disease.

Care and Maintenance

Proper nail care includes keeping the nails clean and dry, trimming them regularly, and avoiding biting or tearing them. Moisturizing the nails and cuticles can prevent dryness and cracking. It is also important to avoid using harsh chemicals that can damage the nails.

See Also

• Keratin
• Claw
• Hoof
• Psoriasis
• Onychomycosis
• Paronychia