kynnenlevy

Kynnenlevy is the Finnish term for the nail plate, the hard, keratinized cover at the dorsal surface of the digits in humans and many other mammals. It forms the visible part of the nail and rests on the underlying nail bed, bounded by the proximal and lateral nail folds. The plate is produced by the nail matrix, a region of specialized keratinocytes located under the skin at the base of the nail. As cells proliferate in the matrix and keratinize, they move outward, forming the layered structure of the nail plate. A pale crescent called the lunula is often visible at the base of the plate where the matrix activity is greatest.

Anatomy and growth: The nail plate comprises several thin, tightly packed layers of dead keratinocytes. Growth occurs proximally in the matrix, with gradual forward advancement of the plate over the nail bed. Fingernails typically grow about 2 to 3 millimeters per month, while toenails grow more slowly, roughly 1 millimeter per month. The surrounding cuticle and nail folds help protect the matrix from infection and injury.

Function: The kynnenlevy protects the fingertip or toe tip, aids in grasping and manipulating small objects, and contributes to tactile sensation by allowing the underlying skin to be exposed through the translucent plate.

Clinical relevance: Conditions affecting the nail plate include fungal infections (onychomycosis), psoriasis, trauma-related changes such as transverse ridges (Beau’s lines) or deformities from matrix injury, and paronychia. Diagnosis is usually clinical, with dermoscopic examination or, rarely, biopsy in unclear cases. Treatment depends on the underlying cause and may involve antifungal therapy, protective measures, or surgical intervention to address matrix damage.