<unk>  are deep grooved lines that run from side to side on the fingernail. They may look like indentations or ridges in the nail plate that could be a sign of stress.<unk>  are the result of a temporary cessation of cell division in the nail matrix, and they are associated with many serious conditions.
Beau's lines
McBurney's point
Kerley lines
Muehrcke's lines
Cook's distance
Beevor's axiom
Mees' lines
Phrygian cap