Concave nail

What it means

The natural longitudinal (posterodistal) convex arch is not present or is inverted.

Koilonychia literally means spoon nails. This often results in a saucer- or spoon-shaped nail and the free edge of the nail is typically everted. The affected digits should be specified. Note that the bundled term koilonychia is an abnormal shape of the fingernail where the nail has raised ridges and is thin and concave.

Rare diseases that can present with this7

The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.

Part of the broader category

Also called: Koilonychia