Nail Anatomy & Disorders Flashcards

Onychoschizia, or lamellar nail splitting, most commonly results from:

Answer: Repeated wetting and drying cycles

Repeated exposure to water and detergents weakens the distal nail plate, causing horizontal layered splitting.

Which nail finding is considered a classic sign of psoriasis?

Answer: Oil-drop (salmon patch) discoloration

The salmon-patch or oil-drop sign in psoriasis appears as a yellow-pink discoloration of the nail bed visible through the plate.

The cuticle (eponychium) functions mainly to:

Answer: Seal the space between the nail plate and proximal fold to prevent infection

The cuticle acts as a protective barrier sealing the proximal nail fold against bacterial and fungal pathogens.

Half-and-half nails (Lindsay's nails) are most strongly associated with:

Answer: Chronic renal failure

Half-and-half nails show a proximal white half and distal red-brown half and are classically linked to chronic renal failure.

In distal lateral subungual onychomycosis (DLSO), the infection typically begins at the:

Answer: Hyponychium and distal nail bed

DLSO starts at the hyponychium and progresses proximally along the nail bed, causing subungual hyperkeratosis and onycholysis.

Retronychia is best described as:

Answer: Proximal embedding of the nail plate into the proximal fold due to upward growth

Retronychia occurs when a new nail plate grows under the old plate, pushing it backward into the proximal fold causing inflammation.

Which of the following nail changes is most characteristic of alopecia areata?

Answer: Geometric pitting in a grid-like pattern

Alopecia areata classically produces geometric or grid-like nail pitting due to matrix inflammation.