Nail plate

The nail plate (Body of nail) is a hard, laminated, keratinized structure that forms the visible part of the nail unit and covers the dorsal aspect of the distal phalanx.

It is composed of tightly packed, anucleate corneocytes derived primarily from the nail matrix, with contributions from the nail bed.

The nail plate consists of three distinct layers: the dorsal, intermediate, and ventral plates, each characterized by specific orientations and types of keratin filaments. The intermediate layer, which accounts for approximately two-thirds of the nail plate's thickness, contains hair-type α-keratin filaments oriented perpendicular to the growth axis, while the dorsal and ventral layers contain stratum corneum-type keratin filaments oriented both parallel and perpendicular to the growth axis. This multilayered "sandwich" structure provides the nail plate with its mechanical rigidity and resistance to deformation.

The nail plate lies atop the nail matrix (proximal 15–25%), the nail bed (distal 75–85%), and extends to the hyponychium at its free edge. It is bordered proximally and laterally by the lateral folds, with the cuticle (eponychium) adhering to its superficial surface at the proximal end. The ventral surface of the nail plate is slightly serrated, facilitating strong attachment to the underlying nail bed and contributing to the forward growth of the nail. The nail plate is colorless and translucent, allowing the vascular nail bed to impart a pink hue.

Its primary function is to protect the distal digit and provide counterpressure for tactile sensation.