Toenails often appear to be alive due to their continuous growth and sensation. However, the visible nail plate is composed of non-living cells. Any growth or sensation comes from the living tissues underneath and around the nail.
The Building Blocks of Toenails
Toenails are primarily composed of alpha-keratin, a tough protein also found in hair and skin. This protein forms the nail plate, the visible and hardest part of the toenail. The nail plate consists of several layers of dead, compacted cells, making it strong yet flexible.
The nail unit encompasses various structures, some living and some not. The nail plate is attached to the nail bed, the soft tissue beneath it, which contains nerves and blood vessels providing nourishment. The cuticle, a thin layer of skin, creates a protective seal where the nail emerges, safeguarding the living nail matrix from infection. Other surrounding living tissues, such as the eponychium, paronychium, and hyponychium, support and protect the nail unit.
The Growth Cycle of Toenails
Toenails grow from the nail matrix, an active tissue located at the base of the nail, beneath the skin. This matrix is where new nail cells are generated. As new cells are produced, they push older cells forward and outward.
This process involves keratinization, where cells harden and flatten, losing their nucleus and becoming non-living as they form the nail plate. Toenails grow at an average rate of about 1 millimeter per month, significantly slower than fingernails.
Why Toenails Appear to Be Alive
The perception that toenails are alive often stems from experiencing pain or noticing changes in their appearance. When a toenail is injured, the pain originates not from the non-living nail plate, but from the highly innervated nail bed and the surrounding living tissues. The nail bed contains a network of nerves and blood vessels, which are sensitive to trauma.
Changes in nail appearance, such as discoloration, thickening, or texture alterations, can indicate underlying health issues. These changes reflect the health of the living nail matrix or broader systemic conditions. For example, yellowing or thickening can signal a fungal infection, while ridges might point to temporary interruptions in nail growth or other health concerns.