Healthy nails are pink because of sufficient blood supply, with smooth and round surface and moderate thickness; The shape is smooth and flat, and there are no vertical and horizontal grooves and interference spots on the surface; The nails are symmetrical, not skewed, without depression or upward inclination of the ends.
Put ten nails in the sun to observe, and move your fingers up and down. If there is shiny reflection on the nail surface, it means that the overall health is in an excellent state and the functions of various organs in the body are intact and normal.