A
wrinkle, also known as a rhytide, is a fold, ridge or crease in the
skin. Skin wrinkles typically appear as a result of
aging processes such as
glycation, habitual sleeping positions, loss of body mass, or temporarily, as the result of prolonged immersion in
water. Age wrinkling in the skin is promoted by habitual facial expressions, aging, sun damage, smoking, poor hydration, and various other factors.