INTRODUCTION
In virtually all women, since the beginning of recorded history, full lips have been associated with youth, beauty, and voluptuousness. Robust, pouty lips are considered to be sexually attractive by both men and women. According to market research firm NPD Group, US sales of lip color reached $290 million for 2011, an increase of 13% from 2010, while sales of lip-gloss were approximately $182 million.1 Even in a period of economic downturn, women continue to buy products to adorn their lips. The "lipstick index," a term coined by Leonard Lauder, Chairman Emeritus of Estee Lauder, Inc., in 2001, describes the phenomenon of increased lipstick sales during an economic downturn.2 Women would rather spend on little luxuries when purse strings are tighter and the economy is uncertain. Lipstick is that one affordable luxury that makes women feel pampered and more confident. Women with beautiful lips feel more beautiful and are likely to be more optimistic.
In youthful Caucasian lips, the ideal vertical height ratio of the upper lip to the lower lip is 1:1.6 (Figure 1).3 The fundamental proportions of the lips change as one ages, however, with lengthening of the cutaneous portion of the upper lip and volume loss and thinning of the upper lip vermilion (Figure 2). Genetics, intrinsic aging, sun exposure, smoking, and repetitive pursing of the orbicularis oris muscle produce angular, radial, and vertical "lipstick bleed lines" (Figure 3). Gravity, osteoporosis, dental changes, maxillomandibular bony resorption, and further soft tissue volume loss at the oral commissures cause the commissures to turn downward in a perpetual frown (Figure 4). Midfacial aging with ligamentous laxity in the cheeks causes the formation of jowls and vertical geniomandibular ("marionette") lines that extend downward from the oral commissures to the mandible. In addition to this hard and soft tissue volume loss, the lip margin itself may become blunted with flattening of the philtrum columns and loss of projection of the Cupid's bow (Figure 5).4-6 Aging also leads to pallor of the vermilion that results in the loss of sharp vermilion-cutaneous junction demarcation.
While aging Caucasian men and women have similar hard and soft tissue volume loss with thinning of the vermilion and cutaneous portions of the lips, men generally do not develop rhytides of the upper and lower lips. This is because men have thicker skin with more subcutaneous fat surrounding terminal hair follicles (as opposed to the fine vellus hairs in women).
Certain ethnic groups, such as Blacks, genetically have greater volume in their lips. The increased melanin in their skin is protective throughout their lives. Consequently, their skin is less prone to solar elastosis. They rarely develop radial rhytides in the lips and their vermilion tends to retain its volume throughout their lives.
The volume and, therefore, the vertical height of the vermilion of the upper and lower lips should fit within the framework of Phi—the Divine Proportion or the Golden Ratio—1:1.618. This begins with DaVinci's classic proportions of the lips relative to the rest of the face. These basic artistic principles from hundreds of years ago still apply today. One can summarize these proportions as follows:
