Human Nails - Structure and Conditions Affecting Nail

Human Nails

Dr.Surya Rao Poodipeddi profile Authored by Dr.Surya Rao Poodipeddi on 2 Jan 2014 - 16:30.

Humans of both sexes have ten fingers, five on each hand and ten toes, five on each foot. In all they have 20 nails one for each finger and toe. In rare and exceptional cases some have more than five fingers and /or toes in which case they have more than 20 nails.

A nail is a type of modified skin, harder than the normal skin, not only adds beauty to the skin but also protects the sensitive tips of the digits. A human can live without a nail but they are good indicators of a person’s general health. Any illness in a person affects the growth of the nails. Nails provide support for the tips of the fingers and toes, protect them from injury and aid in picking up small objects, to scratch or help in tying / untying a knot.

Structure: Nails are formed from the epidermis and mainly consist of hardened skin cells that contain keratin. The skin below the nail is called matrix. The underlying dermis below the larger part of the nail called the nail plate is pink in color due to nourishment from the blood vessels underneath. The whitish crescent-shaped area behind the pink part is called the lumula.

Each finger and toe has a deep fold of skin from where the nails grow. The cells in the epidermis below the nail root move upward to the surface of the skin and increase in number. Those closest to the root become flattened and pressed tightly together. Each cell gets transformed into a thin plate, several such layers pile up to form a nail. The cells which continue to accumulate the nail are pushed forward. Finger nails grow three to four times faster than the toe nails. Like hair, nails grow more rapidly in summer months than in winter. If a nail is torn, it will regrow if the matrix is not severely injured. Sometimes we find white spots on the nails due to temporary changes in the growth rate of a nail.

Conditions affecting the nails:

There are several conditions, which can affect a nail. The most common ones are:

Nail Pitting: Though nail pitting can occur in healthy nails it is commonly encountered in a skin disease called psoriasis where deep pits are formed in the nails. Nail biting: This is mainly due to a habit from childhood. Some continue to bite nails even as adults. Some foul tasting substances are applied to stop this bad and somewhat harmless habit except when there is infection in the skin surrounding the cuticle or the nail.

Ingrown toenails: This commonly occurs in the big toe when the nail pierces the skin surrounding it causing pain and swelling. Shoes that don’t fit properly, injuries to the foot or the toe and improper trimming of the nails are some of the causes for this malady. Treatment consists of surgical removal of part or whole of the affected nail and use of appropriate antibiotics.

Subungal hematoma: This condition is caused by an injury to the nail usually due to hard direct blow like sudden shutting of a door over the nail. If the blow is very severe the nail may get separated from the bed and may even fall of. Cold compressors help relieve the pain. One needs to drain the blood from the hematoma to prevent the nail from falling off.

Bacterial infections: of the nail include paronychia an infection behind the cuticle of the nail, which can form an abscess. This commonly occurs when one gets the nails trimmed in a saloon where the instruments used are not properly sterilized. Drainage of the abscess through an incision and use of antibiotics helps restore normalcy.

Fungal infections of the nail include Tenia unguium. It is due to fungal infection and otherwise known as ringworm of the nail when the nail gets discolored. Treatment lies in administering antifungal agents over a prolonged period.

Nail-patella syndrome is a rare congenital disorder where apart from abnormalities in the kidneys, joints and bones the fingernails are affected causing pitting and ridges on the fingernails.

*Disclaimer: This is not medical advice. The content is for educational purposes only. Please contact your doctor for any health care issues.