[Ethnic variations of scalp hair].

There has been no polytypical variation in human hairforms for at least the last 10,000 years. In view of the wide variety of hair forms, it must be assumed that biological adaptation has occurred. Several features of the scalp hair, such as form, color, thickness, density, maximal length, tensile strength, etc. are clearly genetically determined. When dealing with diseases of the hair, it may be useful for the dermatologist to distinguish between "hair" and "hair".