Tips and toes
QUESTION: Why do fingernails grow faster than toenails?
R. Dwarakanath Rao, Guntakal, A.P.
ANSWER: Our fingernails are made up primarily of dead cells, a horn-like material called keratin. Growth takes place in the matrix, the hidden part of the nail under the cuticle (the tissue that overlaps with the visible part of the nail and rims the base of the nail). The older cells die and harden as they are pushed out. The matrix also includes the lunula, the whitish half-moon area at the base of the nail. Fingernails grow about 0.1 mm per day or 36 mm a year, and toenails grow at about 14 mm per year.
The primary function of nails is to protect the fingertips from injury. While the scientific community is not completely clear about why fingernails grow faster, here are two possible explanations:
i) Since we use our fingers more often, it is more prone to injury and the body needs to replenish any damaged nails fast
ii) It is known that nails grow faster when the temperature is higher, for example more in summer than winter. Fingers are constantly exposed to sun and air during the day whereas toes inside slippers or shoes are more damp and receive less light, affecting the growth rate.
Ravishankar. A, Chennai
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