nail [AS, naegel] , 1. several flattened layers of hard, keratinized epithelial cells with a horny texture at the end of a finger or a toe. Each nail is composed of a root, body, and free edge at the distal extremity. The root fastens the nail to the finger or the toe by fitting into a groove in the skin and is closely molded to the surface of the dermis. The nail matrix beneath the body and the root projects longitudinal vascular ridges, which are easily visible through the translucent tissue of the body. The matrix firmly attaches the body of the nail to the underlying connective tissue. The whitish lunula near the root contains irregularly arranged papillae that are less firmly attached to the connective tissue than the rest of the matrix. The cuticle is attached to the surface of the nail just ahead of the root. Also called unguis. 2. any of various metallic nails used in orthopedics to fasten together bones or pieces of bone.
