Nail anatomy

crescent-shaped whitish bed of a fingernail or toenail

In human anatomy, the eponychium is the thickened layer of skin at the base of the fingernails and toenails. It can also be called the medial or proximal nail fold. Its function is to protect the area between the nail and epidermis from exposure to bacteria. The vascularization pattern is similar to that of perionychium. The eponychium differs from the cuticle – the eponychium is made up of live skin cells whilst the cuticle is dead skin cells.

The hyponychium () is the area of epithelium, particularly the thickened portion, underlying the free edge of the nail plate on the nail. Its proximal border is immediately distal to distal limit of nail bed—a.k.a. the onychodermal band (the line along the interface of the nail bed and the nail plate). Its distal border the free edge of the nail plate—or where that edge would project downwards onto the epidermis.

physical human trait