Nail

Nails are found only in primates, there are a large number of nerves to the nail bed, so very painful when removed.

The nail is a horny plate which forms a protective covering on the dorsal surface of the terminal phlanges, toes and fingers. The epidermis of the nail bed is continuous distally with the epidermis of the finger tip. At the junction of this change the horny layer is thickened, this is known as the hyponychium (under the nail). The nail itself is composed of fused epidermal scales which do not desquamate.

The body of the nail plate is translucent and transmits the pink colour of blood vessels in the nail bed. The root is more opaque as cornification and drying are incomplete. The root becomes continuous with the body of the nail over a crescent shaped margin, the lunule.

Above the nail cells of the stratum corneium extend from the nailwall onto the free surface as the eponychium or cuticle.