Most people have twenty nails, ten on the fingers and thumbs, and ten on the toes.
Nails help us manipulate objects and protect the delicate tissues at the tips of the fingers and toes. Although the nails are similar in many respects from time to time their appearance changes, and this often causes unnecessary worry. White spots on the nails are extremely common and usually caused by minor trauma such as the nail being knocked against a desk or car door. They are more likely to appear when a person's job involves working with their hands. For some people white spots appear every now and then simply because it can run in the family.