The Center for Podiatric Care and Sports Medicine

The Anatomy of a Toenail: Why they Thicken When we Age, and More

Posted by on Wednesday, April 3rd, 2013


It’s a good thing we have toenails, or, at least, it used to be a good thing. Back before we were human beings, when we were some earlier version of ourselves, finger and toenails were thicker, more like claws and hooves. They were good tools and helped protect our early ancestors. But what about these days? What purpose do toenails serve now? There doesn’t appear to be a whole lot of information on the subject. Surely they evolved from claws, that seems clear enough. But whether we need them now is another question. Some argue that they protect the foot bones, but people without toenails typically manage just fine. I would suggest that these days the most important role toenails play is as a diagnostic tool. The nails offer a window into overall internal health. Vitamin deficiencies, autoimmune disorders, circulation problems, and fungal infections all paint a picture on the toenail.


What are toenails made of?

Oh, I’m so glad you asked. Toenails are made of onychocytes, a type of cell that forms the nail matrix. The matrix is called keratin – a hard substance that is found in many places throughout the human body. The cells that make up the nail plate are continuously produced, as long as there is adequate blood supply and nutrition. The thickness and width of the nail is directly determined by the size of the matrix, though its shape is determined by the shape of the toe. New nail plate cells push older cells forward, compressing them. The nail root or sinus is at the base of the nail, under the skin.


Why do toenails thicken as we age?

As we get older, the growth rate of toenails begins to decrease. This means the nails are renewed less regularly and the onychocytes begin to pile up. This is typically much more noticeable in toenails since fingernails are buffed, polished, and rubbed more frequently, and these activities thin the nail plate.

Long-term trauma, like wearing high heels, repetitive stubbing, a high level of activity, and other minor injuries, can damage the nail bed, resulting in more thickening. A single injury can do it too: a blow from a fallen object, for example. And if you suffer from secondary nail disorders like nail fungus or poor circulation – from diabetes, heart disease, or another ailment – you may see your nails thicken at an accelerated pace.


If you have any foot problems or pain, contact The Center for Podiatric Care and Sports MedicineDr. Josef J. GeldwertDr. Katherine Lai, Dr. Ryan Minara and Dr. Mariola Rivera have helped thousands of people get back on their feet. Unfortunately, we cannot give diagnoses or treatment advice online. Please make an appointment to see us if you live in the NY metropolitan area or seek out a podiatrist in your area.