NAILS: patrs of nail, structure of nail, nail diseases, clinical applications of nail, myth regarding nails.

Nails

Parts of the fingernail

The fingernail is an important structure made of keratin. The fingernail generally serve two purposes. It serves as a protective plate and enhances sensation of the fingertip. The protection function of the fingernail is commonly known, but the sensation function is equally important. The fingertip has many nerve endings in it allowing us to receive volumes of information about objects we touch. The nail acts as a counter force to the fingertip providing even more sensory input when an object is touched.

Nail Structure

The structure we know of as the nail is divided into six specific parts - the root, nail bed, nail plate, eponychium (cuticle), perionychium, and hyponychium.
Root The root of the fingernail is also known as the germinal matrix. This portion of the nail is actually beneath the skin behind the fingernail and extends several millimeters into the finger. The fingernail root produces most of the volume of the nail and the nail bed. This portion of the nail does not have any melanocytes, or melanin producing cells. The edge of the germinal matrix is seen as a white, crescent shaped structure called the lunula.

Nail Bed The nail bed is part of the nail matrix called the sterile matrix. It extends from the edge of the germinal matrix, or lunula, to the hyponychium. The nail bed contains the blood vessels, nerves, and melanocytes, or melanin-producing cells. 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.

Nail Plate The nail plate is the actual fingernail, made of translucent keratin. The pink appearance of the nail comes from the blood vessels underneath the nail. The underneath surface of the nail plate has grooves along the length of the nail that help anchor it to the nail bed.

Eponychium The cuticle of the fingernail is also called the eponychium. The cuticle is situated between the skin of the finger and the nail plate fusing these structures together and providing a waterproof barrier.

Perionychium The perioncyhium is the skin that overlies the nail plate on its sides. It is also known as the paronychial edge. The perionychium is the site of hangnails, ingrown nails, and an infection of the skin called paronychia.

Hyponychium The 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, also providing a waterproof barrier.

Nail Diseases

Nail diseases are in a separate category from diseases of the skin. Although nails are a skin appendage, they have their own signs and symptoms which may relate to other medical conditions. Nail conditions that show signs of infection or inflammation require medical assistance and cannot be treated at a beauty parlor. Deformity or disease of the nails may be referred to as onychosis.
There are many disease that can occur with the fingernails and toenails. The most common of these diseases are ingrown nails and fungal infections.

Ingrown Nails
Onychocryptosis, commonly known as "ingrown nails" (unguis incarnatus), 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. The relative rarity of this condition in the fingers suggests that pressure from the ground or shoe against the toe is a prime factor. The movements involved in walking or other physical disturbances can contribute to the problem. Mild onychocryptosis, particularly in the absence of infection, can be treated by trimming and rounding the nail. More advanced cases, which usually include infection, are treated by surgically excising the ingrowing portion of the nail down to its bony origin and cauterizing the matrix, or 'root', to prevent recurrence. This surgery is called matricectomy. The best results are achieved by cauterizing the matrix with phenol. Another method, which is much less effective, is excision of the matrix, sometimes called a 'cold steel procedure'

Nail Fungus
An infection of nail fungus (onychomycosis) occurs when fungi infect one or more of your nails. Onychomycosis generally begins as a white or yellow spot under the tip of the fingernail or toenail. As the nail fungus spreads deeper into the nail, it may cause the nail to discolor, thicken and develop crumbling edges — an unsightly and potentially painful problem.

Infections of nail fungus account for about half of all nail disorders. These infections usually develop on nails continually exposed to warm, moist environments, such as sweaty shoes or shower floors. Nail fungus isn't the same as athlete's foot, which primarily affects the skin of the feet, but at times the two may coexist and can be caused by the same type of fungus.

An infection with nail fungus may be difficult to treat, and infections may recur. But medications are available to help clear up nail fungus permanently.

Clinical Application

Nail inspection can give a great deal of information about the internal working of the body as well, and like tongue or iris inspection, has a long history of diagnostic use in cantraditional medical practices such as Chinese medicine.

Pliability: Brittleness is associated with iron deficiency, thyroid problems, impaired kidney function, circulation problems, and biotin deficiency Splitting and fraying are associated with psoriasis, folic acid, protein and/or Vitamin C deficiency. Unusual thickness is associated with circulation problems. Thinning nails and itchy skin are associated with lichen planus.

Shape and texture: Clubbing, or nails that curve down around the fingertips with nail beds that bulge is associated with oxygen deprivation and lung, heart, or liver disease. Spooning, or nails that grow upwards is associated with iron or B12 deficiency. Flatness can indicate a B12 vitamin deficiency or Raynaud's disease Pitting of the nails is associated with Psoriasis. Horizontal ridges indicate stress, and Beau's lines are associated with many serious conditions. Vertical ridges are associated with arthritis. Vertical grooves are associated with kidney disorders, aging, and iron deficiency. Beading is associated with rheumatoid arthritis. Nails that resemble hammered brass are associated with (or portend) hair loss. Short small beds are associated with heart disease.

Coloration of the nail bed:
Mee's lines are associated with arsenic or thallium poisoning, and renal failure. White lines across the nail are associated with heart disease, liver disease, or a history of a recent high fever. Opaque white nails with a dark band at the fingertip are associated with cancer, cirrhosis, congestive heart failure, diabetes and aging. Paleness or whitening is associated with liver or kidney disease and anemia. Yellowing of the nail bed is associated with chronic bronchitis, lymphatic problems, diabetes, and liver disorders. Brown or copper nail beds are associated with arsenic or copper poisoning, and local fungal infection. Grey nail beds are associated with arthritis, edema, malnutrition, post-operative effects, glaucoma and cardio-pulmonary disease. redness is associated with heart conditions. dark nails are associated with B12 deficiency. Stains of the nail plate (not the nail bed) are associated with nail polish, smoking, and henna use.

Markings: Pink and white nails are associated with kidney disease. Parallel white lines in the nails are associated with hypoalbuminemia. red skin at the base of the nail is associated with connective tissue disorders. blue lunulae are associated with silver poisoning or lung disorder. blue nail beds are (much like blue skin) associated with poor oxygenation of the blood (asthma, emphysema, etc). small white patches are associated with zinc or calcium deficiency or malabsorption, parasites, or local injury. receded lunulae are associated with poor circulation, shallow breathing habits or thyroid mysfunction. large lunulae (more than 25% of the thumb nail) is associated with high blood pressure.

Myths
It is a myth that nails and hair will continue growing for several days after death. The appearance of growth is actually caused by the retraction of skin as the surrounding tissue dehydrates (desiccation), making nails and hair more prominent.

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