In human anatomy, the eponychium is the thickened layer of skin at the base of the fingernails and toenails.

[1] It can also be called the medial or proximal nail fold.

The eponychium differs from the cuticle; the eponychium comprises live skin cells whilst the cuticle is dead skin cells.

Its function is to protect the area between the nail and epidermis from exposure to bacteria.

[3] The word eponychium comes from Greek ἐπί (epí) 'on top of' and ὀνῠ́χιον (onúkhion) 'little claw'.