Head spin is also called hair spin, hair spin is related to genetics, mainly refers to the direction of hair spin rotation. The direction of hairspin rotation is mainly single gene genetic control, belongs to the autosomal inheritance, clockwise rotation is mostly autosomal dominant inheritance, counterclockwise rotation is mostly autosomal recessive inheritance. In addition to the direction of rotation, the number and position of hair spins are not directly related to genetic factors, and the hair spins do not grow vertically during growth, but with a certain inclination. Because it is not on the same plane as the scalp, one or several hair vortexes are formed during the embryonic formation process, that is, the hair spiral.