How Fingernails Work

Personal Hygiene ­Image Gallery OK, so we know they're good for scratching and it's fun to paint them. But why exactly do we have fingernails? See more personal hygiene pictures.
Personal Hygiene ­Image Gallery OK, so we know they're good for scratching and it's fun to paint them. But why exactly do we have fingernails? See more personal hygiene pictures.
© mithani

You may have given your fingernails little thought over the years. You know they grow, they break, and they can come in handy for tasks like peeling an orange or removing the protective plastic from a bottle or jar. If you get or give yourself manicures, you may also rely on your nails as an accessory. But beyond this, what function do fingernails serve? Why exactly do we have them?

It turns out that just why we have fingernails is a matter of some debate. The generally accepted reason is that we have nails to protect the tips of our fingers and toes. Fingernails also help us to manipulate small objects. And we all know how useful they are for scratching [source: Encyclopædia Britannica]. However, some scientists argue that without fingernails, the tips of our fingers and toes would have genetically developed to become less sensitive.


By the 20th century, fingernails seemed to be a way to represent status and reflect cultural trends. Sociologists and fashion historians believe that in some decades, such as the 1980s -- when everything was bigger, longer and more sparkly -- long nails represented wealth and leisure, just as a century before, pale skin symbolized not having to toil outdoors. In later decades, as fashion trends began to shift toward a cleaner look, nail trends followed, popularizing the current shorter, well-manicured look [source: Vantoch].

Setting arguments of science aside, fingernails appear to be around for the long haul, and because they are a part of you, they deserve as much care as you give to your skin or your hair. You should also pay attention to your fingernails because changes in fingernail health can function as an early indicator of certain medical problems. A good place to start in understanding how fingernails work is to look at what they're made of -- keep reading to find out.

What are fingernails made of?

In order to understand both how to keep your nails healthy and how they can act as an indicator of health problems, first you have to know that fingernails are made of layers of a protein called keratin. This protein is also found in your skin and hair [source: Mayo Clinic].

But your nails are more than just keratin. Your nails comprise several different components:


  • The nail plate is the part of the nail that you can see.
  • The skin around your nails is referred to as nail folds.
  • The skin that is covered by your nail is known as a nail bed.
  • A cuticle is the tissue that covers the bottom of your nail to protect newly formed keratin as your nail grows.
  • The white half-moon seen at the base of your nail is called a lunula.

[source: Mayo Clinic]

Changes and discoloration to any parts of your fingernails can indicate that something is wrong with your nail health, or even your overall body health. For example, slow or halted nail growth could indicate a health concern that involves more than just your fingertips.

On average, fingernails grow at a rate of about 0.08 to 0.12 inches (2 to 3 millimeters) a month. Therefore, it takes about four to six months for a fingernail to fully regenerate. Interestingly, the nails of the hand you use most often grow slightly faster than the nails of your non-dominant hand [source: American Academy of Dermatology].

Now that you know the general structure of your nails, read on to learn about some of the problems that can develop there.

Fingernail Problems

Your fingernails are resilient, but only to a point. They can be susceptible to a variety of problems and conditions. Many of these conditions are fairly harmless. For example, if you are regularly exposed to water, soap or harsh chemicals, you may notice that your nails have become soft or brittle, and are prone to easy breakage. This kind of damage can be prevented by wearing protective gloves while working with water, soap and harsh chemicals. For brittle nails, try applying a rich lotion or hand cream to your nails and cuticles. For soft nails, you might consider applying a nail hardener, a type of polish that contains protective properties.

For more information about nail care and treatment, read Nail Treatment: Fast Facts.


Another innocuous condition is the development of vertical ridges, which typically appear as you grow older. Your nails may also develop color changes due to injuries. Little white marks are common following minor injuries, and your nails might turn black or purplish if they are injured more seriously. These discolorations usually go away as the injury heals and the nail grows out [source: WebMD].

Other conditions may require intervention on your part. Hangnails, for example, can be painful, as can ingrown nails -- which are when the nail grows into the surrounding skin. Improper care of these types of problems may lead to infections. Some injuries may cause the nail to detach from the nail bed. In such cases, there is nothing to be done -- other than keeping the area clean and protected -- about the nail until the new nail starts to grow back, which typically takes several months.

Although the damage is self-inflicted and only you can prevent it, habitual nail biting is definitely a problem for your nails. Nail biting can lead to serious nail health concerns, such as bacterial infections -- particularly when you bite your nails down to the point that they bleed [source: American Academy of Dermatology].

Certain fingernail conditions typically indicate other, more serious medical problems. To learn more about what your fingernails can reveal about your health, read on.

Fingernails and Health

While most fingernail problems are minor and can be taken care of with a little care and attention, others can be a telltale sign of more serious issues.

Nail discoloration, such as yellow nails, may indicate a respiratory problem, such as chronic bronchitis [source: Mayo Clinic]. Yellow nails can also indicate systemic issues, such as lymphedema of limbs, which is a buildup of lymph fluid that causes your limbs to swell, or pleural effusion, which is when fluid builds up around your lungs and chest cavity. Nails that are half white and half pink may indicate renal failure [source: The Merck Manuals]. Nails that turn black, brown or purple without being injured may point to melanoma [source: WebMD]. And if your nail beds are pale, it can indicate that you are suffering from anemia [source: The American Academy of Dermatology].


For those with diabetes, the disease can affect many parts of the body, including the nails. Untreated or unchecked diabetes can reveal nails that are yellowish, with a slight blush at the base. Tumors and warts can form under fingernails. As the tumor or wart grows, it can affect the growth of the nail and the surrounding skin.

Although unusual, nails can detach from the nail bed without apparent cause. This could be due to a condition called psoriatic nails. About 50 percent of people with psoriasis (a skin disease that develops when skin cells grow too quickly and form scaly patches on the skin) have exhibited psoriatic nails. Symptoms of psoriatic nails include pitted nails, white pockets under the nail plate that indicate air bubbles, crumbling of the nail plate, or complete nail plate detachment or loss. Psoriatic nails are often associated with psoriatic arthritis [source: PsoriasisNet].

Now that you know a few things about your fingernails and nail health, you may be wondering what you can do to prevent some of the more common problems. To find out, check out the next page.

Caring for Fingernails

Basic nail care is fairly simple, and contributes greatly to overall nail health. By incorporating nail care into your normal routine, it also allows you to grow familiar enough with your normal nail health to notice when abnormal issues arise.

The first step is to keep your nails clean and dry to prevent bacterial and fungal infections, and never cut or remove your cuticles, as this can cause infections. Improve the strength of your nails by trimming them straight across and rounding them slightly with a nail file. This also helps to prevent ingrown fingernails. File nail snags as soon as possible to prevent them from catching on things such as clothing, which can tear the nail into the nail bed [source: American Academy of Dermatology]. Prevent damage by rubbing hand lotion into your nails and nail bed. This will help to strengthen your nails and prevent splitting. Also, try to avoid using your nails to pick or pry at things, as this can also cause damage to your nails [source: Mayo Clinic].


One of the most important things you can do is not bite your nails. As mentioned earlier, nail biting can cause infections not only around your nails, but also in your mouth. Chronic nail biting can lead to abnormal nail growth, and even nail deformities. To prevent nail biting, try applying acrylic nails or use a bitter-tasting polish until you are able to break the habit. Because nail biting is often a stress-associated activity, consider learning a stress management technique, such as yoga or meditation, that works for you [source: WebMD].

Whether you wear them short and unpolished or use them to express your personality by adorning them with color and jewels, nails -- and their health -- are important, so don't neglect them. Not only are they a canvas for self-expression, they also tell us when we might be ill, so be sure to give your fingernails the attention they deserve.

Lots More Information

Related HowStuffWorks Articles

  • American Academy of Dermatology. "Nail Fungus & Nail Health." 2008 (Accessed 10/4/09)
  • American Congress of Obstetricians and Gynecologists. "Skin Conditions During Pregnancy." 2/08 (Accessed 10/04/09)
  • Encyclopædia Britannica. "Nail." (Accessed 10/3/09)
  • KidsHealth. "Your Nails." 3/07 (Accessed 10/04/09)
  • Mayo Clinic. "Nails: How to keep your fingernails healthy and strong." 11/30/07 (Accessed 10/3/09)
  • PsoriasisNet. "Psoriatic Nails." American Academy of Dermatology. (Accessed 10/4/09)
  • The Merck Manuals. "Nail Disorders: Deformities." 11/05 (Accessed 10/04/09)
  • Vantoch, Vicki. "Fingernail Fashion Choices." 12/28/99 (Accessed 9/3/09)
  • WebMD. "Nail Biting -- Topic Overview." 11/13/08 (Accessed 10/04/09)
  • WebMD. "Nail Problems and Injuries -- Topic Overview." 11/13/08 (Accessed 10/03/09)