Fingernails

Fingernails are hard plates composed primarily of keratin that cover the dorsal surfaces of the fingertips. They sit on the nail beds and protect the distal phalanges, while aiding fine motor tasks by increasing the surface area for grip and enhancing fingertip sensitivity. The visible nail is the nail plate, which overlies the nail bed, and is produced by the nail matrix located under the proximal nail fold. The cuticle (eponychium) and the hyponychium at the distal edge help seal the nail unit from infection. A pale crescent called the lunula marks the visible portion of the matrix.

Growth occurs as living cells in the matrix proliferate and keratinize into the nail plate. Fingernails grow at roughly 3 millimeters per month and typically take about 4 to 6 months to fully replace. Toenails grow more slowly. The nail plate is transparent, so color of the underlying tissue shows through, and its appearance can reflect health status.

Common care emphasizes trimming straight across, avoiding aggressive pushing of cuticles, and keeping nails dry and clean. Moisturizing, gentle filing, and avoiding harsh chemicals help prevent damage. Protective gloves reduce trauma when hands are exposed to moisture or chemicals.

Nail changes can signal health issues. Infections such as onychomycosis or paronychia; structural changes including koilonychia (spoon nails), pitting, Beau’s lines, or clubbing; or subungual hematomas after trauma may warrant medical evaluation. Regular nail hygiene and seeking care for persistent changes support nail health.