There is a herringbone seam between the parietal bone and occipital bone, and a coronal seam between the parietal bone and the frontal bone, so there is a depression. The depression of the yogi's head is a normal physiological phenomenon, which is gradually formed during the development of the skull. The concave is the same as the texture of the surrounding skull to the touch, and there is no obvious boundary with the texture of the surrounding skull.