Monday, May 9, 2011

Direction of Nail Growth and Thickness

The matrix cells point at an angle toward the cuticle as shown in Figure 2.3. This creates the flat and thin shape of the plate. The length of the matrix determines the thickness of the natural nail plate. Figure 2.4 shows how this occurs. Clearly, the matrix making the longest row of cells will have the tallest stack of cells in the plate. Of course, a real nail plate has thousands of packed cell layers.



Look closely at Figure 2.4 and you will see something else interesting about nail plate growth. This diagram shows that the cells near the back of the matrix have much further to travel before they get to the free edge. The cells coming from the back of the matrix end up on top of the plate. Since they travel further, they must be older than cells below them. At the free edge the surface plate cells are nearly two months older than the cells on the bottom side. This may explain why thin, dry nail plates tend to peel at the top surface, rather than from underneath.

Sunday, May 8, 2011

How Does the Nail Plate Grow?

As keratin cells are pushed from the matrix they begin to change. They slowly lose their plump, round shape, as shown in Figure 2.2. When they flatten, most of the whitish material inside the cell is lost. They become thin, flat, transparent nail cells. If you recall, the distal part of the matrix is just below the lunula. Most of the lunula area cells haven’t completely flattened or lost their inner material. This explains why the lunula is whitish and cloudy. When the cells flatten, they also become more compact. Older cells pack together more tightly making the nail plate harder or more dense, so near the eponychium (proximal nail plate), the plate is softer. The free edge contains the oldest, flattest, and hardest cells.



It is very important to treat the area near the cuticle with care. It is thinner and softer than the rest of the plate. Also, the matrix is directly below this region. Remember, the eponychium tissue is a barrier against bacteria and other microscopic invaders. It must not be broken or harmed. Always use caution with any procedure involving this area of the nail unit. Damage here can permanently injure the nail unit.

For many years, it was believed that at least part of the nail plate grew up from the nail bed. Every cell in the nail plate comes from the matrix. The only exception is the thin layer of epidermis that adheres to the bottom of the plate. This tissue becomes the solehorn found under the free edge of the plate.

Saturday, May 7, 2011

The Role of Proper Circulation

The matrix needs a good blood supply in order to do its job. Arteries carry nutrients to tiny capillaries in the matrix. Capillaries are like long, one-way streets. They wind through tissue carrying blood. The matrix has two types of capillaries. One type delivers oxygen, and important nutrients to matrix cells. The other drains waste products and other contaminant’s away from the matrix.

The draining capillaries carry wastes to the veins. The impure blood flows through the kidney and liver where it is purified and returned to the heart. The heart pumps the blood to the arteries which circulates it throughout the body. This cycle runs continuously, 24 hours a day. Every cell in the body benefits from this cycle, including those of the nail unit. This is how the matrix is fed and cleaned. Obviously, proper circulation is a critical part of maintaining a healthy nail unit.

Friday, May 6, 2011

The Onychodermal Band

This feature of the nail unit is often missed. It can only be seen with careful observation. The onychodermal band is found in the nail plate, just before the free edge. Examine your own nails for this band. This thin band has a glassy-looking, grayish appearance. You will see this grayish band lying beside the nail plate’s white free edge. This is the seal between the nail plate and hyponychium. When this seal is broken, infection often occurs.

Thursday, May 5, 2011

Nail Plate Growth

How fast does the nail plate grow? This is a difficult question to answer. Many factors affect the growth rate. For example, the nail plates of each finger grows at different rates. Nail plates also grow slower at night and during the winter. On the average, the normal thumb nail will grow about 1/10 inch per month or 1 l/2 inches per year. The left thumb nail usually grows slightly faster than the right. The index fingernail plate grows the fastest, followed by the pointer and ring finger, which grow at almost the same rate. The thumb’s is the next slowest, but the slowest of all is the little finger’s. It grows abou1t I/4 inches per year.A s a rule, the longer the finger the faster the nail plate will grow.

Nail plates grow about 20% faster in the summer. They also grow faster during pregnancy. Nail plate growth increases by about 3 l/2% between the fourth and eighth month of pregnancy. From the ninth month until after delivery, growth rate increases by 20%, regardless of season. After two or three weeks the growth rate drops back to normal. Age also affects the growth rate. Growth peaks between the ages of ten and 14 years and slowly declines after age 20. Nail-biting, accidental damage, or loss causes nail plates to grow faster. Men’s nail plates grow faster than women, especially on the dominant hand. Many factors cause slow growth of nail plates. For example, being immobilized or paralyzed, poor circulation, malnutrition, lactation, serious infections, psoriasis, and certain medications.

Some believe that certain foods, (i.e,, gelatin or using special creams and oils), will increase the growth rate. This is untrue. Although the nail plate requires certain nutrients for proper growth, there is little evidence that eating any particular foods will cause them to grow faster. Creams, oils, and lotions are sometimes sold as “growth accelerators.’’ These claims are false, misleading, and illegal! No cosmetic product may claim that it will change or alter any body function. These products and other cosmetics are for beautifying only, not healing. Only medical drugs can make such claims. Remember-no cosmetic-related product can heal, repail; grow, or make any other similar claim.

Wednesday, May 4, 2011

The Hyponychium

The farthest or most distal edge of the nail unit is the hyponychium. It is found under the free edge. The hyponychium is composed of epidermis tissue. As you know, this same tissue makes up the top layer of the nail be(ds ee Figure 1.2).

The hyponychium forms a watertight seal that prevents bacteria, fungi, viruses, etc., from attacking the nail bed. Care should be taken when manicuring under the free edge. Damage to the hyponychium can lead to infection. Once infected, the natural nail plate may lift or separate from the nail bed. It may even lead to loss of the nail plate.

Tuesday, May 3, 2011

Nail Blood and Nerve Supply

A rich supply of nutrients is delivered to the nail unit by the blood. Arteries carry blood from the heart to other parts oft he body. Two arteries supply each nail unit. A single artery runs along each side of the finger passing through the lateral nail fold. After leaving the nail fold, they run deep into the dermis (basement tissue) of the nail bed. Many small branches carry blood from the arteries to other parts of the nail unit. These tiny branches are called capillaries. The capillaries give the nail bed its pinkish color. The capillaries carry blood to the epidermis, just below the nail plate. The result is a healthy pink appearance. The capillaries do not reach into the nail plate. Therefore, the nail plate receives no blood or nutrients. Blood is drained away from the nail unit by veins. Veins collect blood from the capillaries and return it to the heart. The nail unit has two veins. Each lateral nail fold has its own vein. These veins carry blood and waste products away from the nail bed. Figure 1.5 shows the complex system of veins, arteries, and capillaries found in the hand and finger.

Nerves follow a similar path through the nail unit. Nerves provide the sensations of touch, pain, and warmth. They also move the muscles in the fingers and hands. The nerves end near the skin’s surface. The nerve endings are very sensitive. Some are sensitive to pain, some to pressure and others to heat. They relay these sensations back to the brain.

Monday, May 2, 2011

Solehorn

The epidermis remains attached to the underside of the nail plate until it grows past the fingertip. This epidermis can be seen by closely examining the underside of the free edge. This is called the solehorn or solehorn cuticle. The solehorn usually sloughs away on its own or may be removed during a manicure.

Sunday, May 1, 2011

Nail Bed

The nail bed lies directly under the nail plate. It starts at the matrix and ends just before the free edge. Like skin, the nail bed is made of two types of tissue, dermis and epidermis. The dermis is the lower or basement layer of tissue (found just below the epidermis). The epidermis is the upper layer and is closest to the nail plate. These two skin layers have unique shapes. The dermis has many grooves or channels running from the lunula to just before the free edge. The epidermis has ridges or rails running the same direction. These ridges fit neatly into the channels found in the dermis as shown in Figure 1.4.

The dermis is attached to the bone underneath. Therefore, the dermis is locked into place and does not move. Thee pidermis is very different. its firmly attached to the underside of the nail plate. So, the epidermis moves with the nail plate as it grows. This happens because the ridges of the epidermis are free to slide in the channels of
the dermis.

As the nail plate grows, the channels act like many sets of train tracks, guiding the ridges of the epidermis. Besides keeping the nail plate “on track,” the grooves also hold the ridges in place. This prevents the nail plate from lifting off the nail bed. he nail bed does not add keratin cells to the nail plate. All nail growth occurs in the matrix under the proximal nail fold and lunula.

Saturday, April 30, 2011

Nail Lunula

The lunula (half-moon) is the whitish, opaque area at the base (proximal end) of the nail plate. The plump, white keratin cells flatten like pancakes. When they flatten, most of the material inside the cell is lost. This is why the cells become transparent. The lunula is formed by cells that have not yet completely flattened or lost their inner material. Not all fingers have a lunula. On fingers with a lunula, the front end of the matrix is directly below the whitish area. The h u l a outlines the front part of the matrix. The lunula is usually seen on the thumb and index finger. Interestingly, you can tell if a person is right- or left-handed by which thumb has the largest lunula. The thumb with the largest lunula is on the dominant hand.

The lunula also determines the shape of the nail plate. Look at the shape of your lunula and compare it to the natural shape of the nail plate’s free edge. They are an identical match. Both the lunula and free edge are crescent shaped. As mentioned above, it is also the shape of the distal (front end) part of the matrix. Animals with different-shaped lunulas have nail (or claws) which also match in shape. Figure 1.3 shows the claw and lunulas hapes of six different types of primates.’ Notice that the shape of the lunula closely matches the free edge.

Friday, April 29, 2011

Nail Plate

The nail plate is mostly keratin, the same chemical substance that forms hair. Keratin is a protein made from amino acids. These special proteins form a strong, flexible material which we call the nail plate. The nail plate is made of many layers of dead, flattened cells. These plate-like cells are cemented to each other with a sticky substance. When many layers stick to each other they form a structure that resembles a mortar and brick wall. The nail plate is also called the natural nail.

After a keratin cells grows in the matrix it is pushed outward and slightly upward by newer cells. The new growth emerges from under the proximal nail fold at the eponychium (see Figure 1.2). As new cells leave the matrix, they push the older cells toward the fingertips. Eventually, each keratin cell will reach the end of the finger. The part of the nail plate that grows beyond the fingertip is called the free edge or the distal nail plate. Distal means “farthest from the attached end.” It is important to remember the difference between distal and proximal. Proximal means “nearest attached end”. Therefore, distal is the opposite of proximal. These words may seem strange at first, but they are important to understand.

The hard keratin plate protects the nail bed and fingertip. Thicker nail plates provide greater protection. Obviously, if the nail plate is thinned too much, it cannot properly protect the delicate tissue underneath. This is often seen in nails that are over manicured or filed. Over filing the natural nail is a leading cause of nail plate thinning and destruction.

When keratin cells leave the matrix they are plump and whitish in appearance. Before emerging from under the eponychium the cells flatten, become transparent, and lose their color. This explains why nail plates are normally colorless, except for the white half-moon at the cuticle.

Thursday, April 28, 2011

Cuticle and Eponychium

The cuticle is a part of the proximal nail fold. Specifically, it is the skin that touches the nail plate. There is more to the cuticle than what is visible. As you have learned, the skin curls underneath to form the proximal nail fold (see Figure 1.1). The skin underneath the fold is different than the visible top surface. The underside of the proximal nail fold constantly sheds a layer of colorless skin. This shed skin attaches to the topside of the emerging nail plate. It then “rides” on the nail plate and seems to grow from under the fold. This is the true cuticle. The visible skin fold that appears to end at the base of the nail plate is the eponychium. Sometimes, this tissue is incorrectly called the cuticle. During a manicure, the eponychium is gently pushed back to expose the true cuticle which should be carefully removed. You will see later that improperly performing this part of the manicure causes many problems for clients. It can lead to service breakdown of artificial nails and may seriously damage the nail unit.

Wednesday, April 27, 2011

Nail Matrix

Directly below the proximal nail fold is a small area of living tissue called the matrix. The matrix is the most important part of the nail unit. The matrix produces cells that form the nail plateT. hese cells are much like those found in a shaft of hair.

The size and shape of the matrix determine the thickness and width of then ail plate. The wider the matrix area, the wider the nail plate. Therefore, the matrix of the thumb must be wider than the matrix area of the little finger. Also, longer matrices make thicker nail plates. A person who has naturally thin nail plates must have a very short matrix area. If the matrix becomes damaged in any way, the effects will be seen in the nail plate.

Tuesday, April 26, 2011

Nail Folds

The skin does not end at the nail plate. Instead it folds underneath and covers the emerging nail plate. This skin fold protects the new, emerging nail plate. This fold is part of the nail unit. It is called the proximal nail fold. Proximal means “nearest attached end.” The skin on either side of the nail plate is an extension of the proximal nail fold, called the lateral nail fold. In this case, lateral means “to the side.” Normally, the proximal nail fold has the appearance of smooth, healthy skin. It can be injured by cuts, nicks and bruises, or irritating chemicals. Once the proximal nail fold is damaged, bacteria, fungi, or viruses can attack and cause infection. The proximal nail fold forms a seal or barrier that protects the area where the nail plate is made.