CORA PRESTON, MD, of Toronto, ON, wonders, "Do longitudinal lines or ridges in the nail indicate a deficiency of something? Is there any significance to this physical finding?" </STRONG> Longitudinal ridging of the nail plate (called onychorrhexis) consists of longitudinal elevations that alternate with depressions or grooves along the nail plate. This can be caused by partial dropout or malfunction of the nail matrix, which will thin the nail plate. Consequently, conditions that damage the nail matrix can cause ridging. Mild ridging is a common innocent feature in the elderly. The mechanism isn't known, but is of no clinical consequence. Severe ridging, however, is prototypic of lichen planus. The disease obliterates the nail matrix, leading to severe thinning or splitting of the nail plate. There's no known deficiency that can cause ridging. On the other hand, deficiency in biotin or iron can soften the plate, leading to deformities. GS (©copyright: Parkhurst Exchange year-month-#: 2003-09-13) just found this does anyone no what sort of deformities???
