Beau's line

[bōz]
n.
  1. Transverse depressions on the fingernails occurring after trauma such as severe febrile disease, malnutrition, or coronary occlusion.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.