nails

nails The replacement of sharp claws with flattened nails in primates is considered part of the evolutionary development of a hand able to grasp objects. The nails start to develop in the fetus by the end of the third month, and are formed from the same epidermal tissue as the skin. They reach the ends of the fingers and toes about a month before birth.

The mature nail is a plate of the protein keratin which is also present in hair and skin. The pale ‘half-moon’ at the base — often exposed above the nail-fold only on the thumbs and big toes — marks the area of the bed of the nail where its substance is formed and from which it grows — the germinal matrix. The rest of the nail bed provides a surface for the growing nail to slide over as it advances at the rate of about 0.1 mm/day. The germinal cells continually divide to replace those which generate, and disappear into the non-cellular substance of the nail. This proliferation can be interrupted by injuries or acute illnesses, leaving grooves across the nails which gradually grow out.

The decoration of both toenails and fingernails for aesthetic purposes dates back at least as far as Ancient Egypt, where henna and other products were applied to colour the feet and hands as well as the nails. Growing long fingernails has also been practised in Chinese and Hindu cultures, in part as a sign of leisure and status, since many forms of manual labour are difficult or impossible with long fingernails. Well-groomed nails have been a sign of cultivation and cleanliness for both men and women in American and European cultures as well. As a 1952 etiquette guide pronounces, ‘A fastidious man … keeps his nails clean and short with the cuticle pushed back. If he has his nails professionally manicured, they may be buffed but should never have any coloured or even colourless polish applied’. Coloured and clear nail enamel, or ‘polish’, became popular for women in the early twentieth century, and often replaced the literal polishing of nails with a buffer. False and elaborately painted nails are also now popular among some cultural groups.

In folk beliefs, the nails are often said to continue to grow after death. For instance, long fingernails, or sometimes no nails at all, are characteristic of vampires, revenants, and other beings of ‘undead’ status. In fact, in decomposition the tissues of the body dehydrate and contract, giving the appearance that the nails, hair, and teeth have ‘grown’. Sometimes the nails are sloughed off with the outer layer of skin, leaving exposed what appears to be new skin or nails, another sign of preternatural ‘life’ in a corpse. This same phenomenon is also the explanation for stories of dead bodies supposedly having come to life in the coffin and having either chewed off their nails in anxiety, or having scraped them off trying to escape. To keep the nails in place, Ancient Egyptian embalmers sometimes either tied the nails to the fingers and toes, or covered them with metal thimbles.

Sarah Goodfellow