DEFINITION of 'Actuarial Life Table'. A table or spreadsheet that shows the probability of a person at a certain age dying before his or her next birthday. These statistics calculate the remaining life expectancy for people at different ages and the probability of surviving a particular year of age. Because men and women have differing mortality rates, an actuarial life table is computed for separately for men and women.
Vertical ridges can also be caused by nail injury and certain diseases, including rheumatoid arthritis, according to Rich. If, instead of a series of ridges, there's a single vertical streak, cautions Krant, this could be a sign of a tumor growing at the root of the nail.
The fingernail 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 a part of the nail matrix called the sterile matrix.