Toenails: Structure, Function & Diseases

Toenails are located at the tips of the toes. They are made of callus and protect the toes from mechanical impact. A number of diseases can be identified by the condition of the toenails. However, they can also be affected by nail disease.

What are toenails?

Toenails are skin-colored, flat structures. They are located on the top of each toe. Toenails harmonize in size with their respective toe. Thus, the largest toe has the largest toenail. The smallest toe also has the smallest nail. Toenails grow about 1 millimeter per month. They are horny plates. They developed from the epidermis due to the necessary protective function. In addition to protecting the toes, toenails also support the gripping function of the foot. Toenails consist of many layers. They are up to 150 layers of horn cells. On average, a toenail is 0.5 millimeters thick.

Anatomy and structure

A toenail consists of a straight nail plate and is stuck in a nail pocket. At the deepest point of the nail pocket is the nail root. There, the toenail is formed from horn plates. The upper part of the nail pocket, which rests on the nail, is called eponychium. It is a thickened layer around the toenail. It protects the nail from bacteria. Eponychium is epithelium, also called covering tissue. At the transition of this epithelium to the visible beginning of the nail is the cuticle. It also has a protective function. The cuticle is covered with a natural fat-water layer. It thus provides a protective barrier against pathogens. Under the nail plate is the hyponychium. This layer of skin protects the nail plate. Beneath this connective tissue-like layer is the nail bed, which is firmly fused to the periosteum. Directed to the nail root, the hyponychium becomes the matrix. This is the place where the nail substance is formed. This area is easily visible as the nail moon. Below the toenail tip is skin with particularly sensitive sensory cells. Thus, the texture of a surface or the hardness can be felt.

Function and tasks

The most important function of toenails is to protect the sensitive toes from mechanical impact and injury. They support the foot during palpation. Furthermore, they enable scratching or scoring. The toenails enable people to perceive pressure in a more differentiated way. The toenail has no nerve cells or blood vessels. Therefore, it does not provide any pain sensation itself. Rather, it provides a defensive shield in the event of accidents. If a toenail is removed due to an accident, it takes about 6 months to grow back. However, it is not certain that a toenail will grow back to the same size and structure. Discoloration may form or the nail may grow to a different thickness and length than before. The appearance of the nails can provide important health clues for a physician. In particular, skin diseases can be easily identified.

Diseases and complaints

A healthy nail is transparent and smooth. If the nail bed is well supplied with blood, the nail looks soft pink. The protruding edge of the nail and the crescent-shaped lunula (nail moon) appear slightly whitish. Only not every toenail shows this ideal. Many toenails are deformed, discolored and appear far from ideal for a variety of reasons. One of the common diseases is nail fungus. Due to it, toenails change, become light yellow and dissolve into crumbs. Due to a nail fungus, the nails detach from the nail bed. Since a nail fungus is contagious, it should be treated as soon as possible. Each nail fungus can be individually different. Therefore, not only self-medication is recommended, but also a timely visit to the doctor. Psoriasis can spread not only on the skin, but also on the toenails. As a result, the nails become porous and offer increased attack surfaces for pathogens. This leads to detachment of the nail plates and to spotted nails. Since the visual symptoms differ only slightly from a nail fungus infection, a nail bed biopsy is often necessary to identify the clinical picture. Each therapy is individually different, but with psoriasis, certain medications that work from the inside usually help. Ingrown nails are mostly quite painful, as they can activate the sensation of pain with every movement. Wrong pedicure can be the reason.To prevent such pain, a visit to a professional pedicurist is beneficial. Longitudinal grooves in the toenails can develop due to age or are already congenital. Transverse grooves in the toenail may have developed after injuries and grow out slowly. Impacts against the toenail can cause whitish discoloration. Although visually not beautiful, only the outgrowth can be waited for. Malformed nails also come in many varieties. A dermatologist can advise accordingly.