<unk>  are lines of discoloration across the nails of the fingers and toes after an episode of poisoning with arsenic or thallium or other heavy metals. They are typically white bands traversing the width of the nail. As the nail grows they move towards the end, and finally disappear when trimmed.
Mees' lines
Kerley lines
Schmidt-Lanterman incisures
Vocal folds
Horror vacui
Ondine's curse
Microtia
Half and half nails