Headline is may be caused by muscle contraction, skin relaxation and aging, and tissue atrophy. 1. Muscle contraction: Due to rich facial expression and muscle contraction, fine lines and wrinkles will appear on forehead, and the forehead lines may be reduced or disappear when the muscles relax. 2. Skin laxity and aging: with age, the fat in the deeper layers of the skin will decrease accordingly, resulting in sagging and loose skin, and thus the appearance of head lines. 3. Tissue atrophy: Due to the atrophy of collagen and fibroelastic tissue in the dermis layer of the skin, the skin loses its flexibility, leading to premature sagging of the skin and the appearance of head lines. If the appearance of head lines, patients are advised to go to the hospital to consult the doctor to clarify the cause.