Dr. Michael Barrett
540 Madison Oak, Suite 130
San Antonio, TX 78258
(210) 479-3233


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

Nail Growth
Nails grow all the time, but their rate of growth slows down with age and poor circulation. Fingernails grow faster than toenails at a rate of 3mm per month. It takes 6 months for a nail to grow from the root to the free edge. Toenails grow about 1 mm per month and take 12-18 months to be completely replaced.

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. Each of these structures has a specific function, and if disrupted can result in an abnormal appearing nail.

Nail Root
The root of the nail 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 toe. The nail 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 toenail, 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.

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

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.

The hyponychium is the area between the nail plate and the tip of the toe. It is the junction between the free edge of the nail and the skin of the tip, also providing a waterproof barrier.

nail anatomy