• Question: how do nails grow ?

    Asked by claire13 to Indi, Jarv, John, Ken, Vicky on 11 Mar 2012.
    • Photo: Vicky Young

      Vicky Young answered on 10 Mar 2012:

      Nails are made of keratin, which is a protein that can become really hard. Nails grow from the base of the nail which is sometimes known as the growth plate. As the nail grows, cells from the area under the base multiply, mature, and die. The nail is then made of several layers of dead, flattened cells which then become filled with this keratin which gives the nail its tough, hard exterior.

    • Photo: Indi Ghangrekar

      Indi Ghangrekar answered on 10 Mar 2012:

      I think Vicky’s covered this question very well already!

      Nail growth can be affected by a lot of factors though, nutrition, age, sex. Sometimes, due to some kind of infection or trauma, nail growth stops for a bit to deal with the bigger problem that is happening elsewhere in the body and it looks like a line going horizontally from side to side across the nail (not the vertical ridges). If your doctor has ever asked to see your hands and examines your nails, that may be one of the things they are looking for. These lines are called Beau’s lines (named after the doctor that discovered them) and because the average growth rate of nails is known, they can then estimate when the trauma or infection happened.

    • Photo: Jarvist Moore Frost

      Jarvist Moore Frost answered on 11 Mar 2012:

      As far as I’m concerned, as a physicist, it’s magic. :: )