Marionette lines are a common sign of skin aging in adults. They appear as long, deep creases in the skin that radiate from the corners of the mouth in a downward direction. Marionette lines are part of the natural aging process. As the skin ages, it loses elasticity and firmness. As a result, fine lines begin to appear and the skin becomes thinner and drier. Habitual movement of facial muscles is major cause for the development of marionette lines. Pursing the lips when frowning repeatedly over time can contribute to the development of permanent wrinkles along the corners of the mouth. Factors such as chronic sun exposure and smoking can often cause these lines to start appearing earlier. Fortunately, facial lines can be reduced with treatment and proper skin care.