Fingernails and Toenails: Structure, Conditions, Care

Author: Disabled World (DW)
Updated/Revised Date: 4 Aug 2026

Table of Contents:
Synopsis - Definition - About This Section - FAQs - Publications - Subtopics

Synopsis

Learn how fingernails and toenails form from keratin, what nail color and shape changes reveal about health, common nail conditions, and daily nail care tips.

At a Glance

• 1 - Nail biting has a medical name, onychophagia.
• 2 - Nails grow faster in summer than they do in winter.
• 3 - Fingernails take 3 to 6 months to regrow fully, while toenails need roughly 12 to 18 months.
• 4 - Nails do not keep growing after death; the skin dehydrates and tightens, making nails and hair only appear longer.

Topic Definition

Nail (Human Anatomy)

A nail is a tough protective plate made of keratin, the same fibrous protein found in the hooves and horns of animals, that covers and shields the tip of each finger and toe. Each nail is a small system rather than a single part, built from the nail plate you see, the matrix at the root where growth begins, the vascular nail bed beneath, and the surrounding folds and cuticle that hold everything in place. Because the matrix records changes over time, the color, thickness, and surface of a nail can reflect general health, and shifts such as ridges, grooves, spooning, or discoloration sometimes point to injury, infection, nutrient shortfalls, or conditions elsewhere in the body. Healthy nails typically look pink where they rest on the bed and turn white as they grow past it.

Overview

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. Fingernails and toenails consist primary of the nail plate, the nail matrix and the nail bed below it, and the grooves surrounding it.

Healthy nails should be a pink color - with the healthy nail plate being pink, and the nail white as it grows off the nail bed. Fingernail color and condition changes are rarely the first clue of serious illness. In most instances, people will show other signs, or symptoms of disease, before nail changes become evident.

Structure of Finger and Toenails

• Nail Cuticle: The cuticle (eponychium) of a nail is the thin layer of skin that covers the nail plate and nail root just before the nail emerges at the surface. The cuticle is not made up of cells, but is a secretion of the epidermal cells.
• Nail Plate: The nail plate - also known as "Body of Nail" or "Corpus Unguis" - is the actual nail, and is made of a translucent keratin protein composed of amino acids.
• Nail Folds: The nail fold is the tissue that encloses the nail matrix at the root of the nail. The nail fold attaches the nail to the rest of the skin through the protective cuticle.
• Nail Matrix: The nail matrix is the part where your nails begin to grow. The nail matrix creates new skin cells that push out old dead skin cells to form both finger and toenails.
• Nail Lunula: A nail lunula, (Latin for little moon), is found at the fingernail bottom. The lunula is the visible part of the root of the nail, and it looks like a curved white mark. The lunula is most noticeable on the thumb; however, not everyone's lunulae are visible. In some cases, the eponychium may partially or completely cover the lunula.
• Nail Bed: The nail bed is defined as; the vascular epidermis upon which most of the fingernail or toenail rests that has a longitudinally ridged surface, often visible through the nail. Nail bed injuries can be painful and may prevent you from using your fingers - however, nail bed injuries are treatable.
• Nail Hyponychium: The nail hyponychium is the area between the free edge of the nail plate and the skin of the fingertip. It also provides a waterproof barrier. The most common infection involves the end of the nail, when fungi invade the hyponychium.
• Nail Free Edge: The end of the nail that extends beyond the fingertip - also known as the Free Nail Angle or the distal nail plate. The free edge is the "dead" or painless part of the fingernail ot toenail.
• Eponychium (Cuticle): The eponychium - or cuticle - is the thickened layer of skin surrounding fingernails and toenails. It can also be called the medial or proximal nail fold.
• Paronychium: The paronychium is the soft tissue border around the nail, and paronychia is an infection in the paronychium area.

Nail Conditions

Major illness can cause a deep transverse groove to form across the nails. A change in fingernail color, thinning, thickening, brittleness, splitting, grooves, Mees' lines and nail ridges, small white spots, receded lunula, clubbing (convex), flatness, spooning (concave) can indicate illness in other areas of the body, nutrient deficiencies, drug reaction or poisoning, or merely local injury. Both Fingernails and toenails can also become thickened (onychogryposis), loosened (onycholysis), infected with fungus (onychomycosis) or degenerate (onychodystrophy)

• Onychia is an inflammation of the matrix (surrounding tissue) of the nail, with formation of pus and shedding of the nail.
• Onychocryptosis, commonly known as "ingrown nails" can affect either the fingers or the toes. In this condition, the nail cuts into one or both sides of the nail bed, resulting in inflammation and possibly infection.
• Onychodystrophy is a deformation of the nails that can result from cancer chemotherapy. It can include discoloration of the nail, or dyschromia.
• Onychogryposis is a thickening and increase in curvature of the nail most commonly seen in the great toe, but may be seen in other toes as well as the fingernails. An affected nail has many grooves and ridges, is brownish, and grows more quickly on one side than on the other.
• Onycholysis is a loosening of the exposed portion of the nail from the nail bed, it is frequently associated with an internal disorder, trauma, infection, nail fungi, allergy to nail enhancement products, or side effects of drugs.
• Onychoschizia or splitting of the nails is a very common problem often seen by dermatologists. The term onychoschizia includes splitting, brittle nails, soft or thin toenails and fingernails.
• Onychomadesis is the separation and falling off of a nail from the nail bed. Common causes include localized infection, minor injury to the matrix bed, or severe systemic illness.
• Onychomycosis, also known as tinea unguium, is a contagious infection of the nail caused by the same fungal organisms which cause ringworm of the skin.
• Onychoptosis is the periodic shedding of one or more nails, in whole or part. This condition may follow certain diseases such as syphilis, or can result from fever, trauma, systemic upsets or adverse reaction to drugs.
• Paronychia is a bacterial or fungal infection where the nail and skin meet.
• Koilonychia is when the nail curves upwards due to an iron deficiency. The normal process of change is: brittle nails, straight nails, spoon-shaped nails.
• Subungual hematoma occurs when trauma to the nail results in a collection of blood, or hematoma, under the nail. It may result from an acute injury or from repeated minor trauma, such as running in undersized shoes.

Fingernail and Toenail Facts

Nails never stop growing, and they must be cut from time to time, however, using nail trimming tools used by different people can transmit nail infections. Use standard hygiene and sanitation procedures to avoid this transmission, in some cases, gel and cream cuticle removers can be used instead of cuticle scissors.

• Nail biting is called onychophagia.
• Nails grow faster in the summer than in the winter.
• Finger and toenails grow at an average rate of 3 millimeters a month.
• Fingernails take 3 to 6 months to regrow completely, while toenails require around 12 to 18 months to grow back fully.
• Contrary to popular belief, nails do not continue to grow after death; the skin dehydrates and tightens, making the nails (and hair) appear to grow.
• Unusual nail shape, such as the nails becoming concave, can be caused by iron deficiency.
• Fungal infections, such as tinea, are spread from one person to another and can affect the fingernails or toenails.
• Nails can be affected by tumors - including squamous cell carcinoma, usually caused by infection with the human papillomavirus (HPV). Melanoma can also impact the nail.
• Some nail conditions are congenital (present at birth). These include nail-patella syndrome, where the nails are improperly formed or missing.
• Skin diseases such as psoriasis, eczema (dermatitis), lichen planus or lupus can alter the nails. Abnormalities may include pits, grooves, or crumbling nails.

See our Amazing Human Body article for more facts and trivia regarding finger and toenails.

Caring for Your Nails

• Apply moisturizer to your nails and cuticles every day. Creams with urea, phospholipids, or lactic acid can help prevent cracking.
• Avoid harsh chemicals such as strong soaps and detergents.
• Avoid nail polish removers that contain acetone or formaldehyde.
• Avoid nail-biting or picking.
• Avoid or limit the handling of chemicals such as hair dyes.
• Bring your instruments if you get frequent manicures.
• Don't dig out ingrown toenails - see a dermatologist if they become bothersome.
• Don't remove the cuticles or clean too deeply under your nails, which can lead to infection.
• Don't clean under your nails too often or too aggressively.
• Don't smoke.
• Eat a balanced diet and take vitamins containing biotin.
• File your nails in one direction and round the tip slightly, rather than filing to a point.
• If you have artificial nails, check regularly for green discoloration (a sign of bacterial infection).
• Keep your nails clean and dry.
• Make sure your shoes are well-fitting and have plenty of room for air movement.
• Moisturize your hands frequently, particularly after washing them.
• Practice good personal hygiene.
• Remember to rub the moisturizer over your nails and cuticles too.
• Remove artificial nails carefully and according to the manufacturer's instructions.
• Resist the urge to bite or tear off hangnails - use nail clippers.
• To protect yourself from fungal infections, don't share towels, always dry yourself thoroughly after bathing (particularly between the toes), and wear thongs in communal bathing areas such as the local gym or swimming pool.
• Treat any sign of eczema on your hands promptly.
• Wear protective gloves for wet jobs such as washing the dishes.
• When giving yourself a home manicure, do not push back the cuticles.

Frequently Asked Questions

Are fingernails and toenails made of the same material

Yes, both fingernails and toenails are made of keratin, the same tough protein, so they share the same basic structure and grow from a matrix at the root.

Why do my nails have white spots

Small white spots are usually the result of minor injury to the nail as it grew and are typically harmless, fading as the nail extends past the fingertip.

How can I tell if I have a nail fungus

Fungal infection often shows as thickening, discoloration, brittleness, or crumbling at the edge of the nail, and a dermatologist can confirm it with a simple test.

Can vitamins improve nail strength

A balanced diet supports nail health, and supplements containing biotin are commonly suggested to help strengthen weak or brittle nails over time.

Why are my nails turning yellow

Yellowing can come from nail polish staining, fungal infection, smoking, or an underlying health issue, so persistent discoloration is worth having checked.

Is it safe to cut cuticles during a manicure

Cutting or pushing back cuticles is best avoided because the cuticle seals the nail against germs, and removing it raises the risk of infection.

How long does it take to grow out a damaged nail

A damaged fingernail generally grows out in 3 to 6 months, while a toenail can take about 12 to 18 months to be fully replaced.

Curated and edited by Ian C. Langtree, Founder & Editor-in-Chief, Disabled World. This section is maintained by the Disabled World editorial team.

Last updated: 4 Aug 2026