Diagnosis and Consultation

Macrocheilia is defined as excessive lip size. Various ethnic groups share the characteristic of larger lips, including African American, Asian, and other groups (Figure 15-1), so for the remainder of this chapter, racial lip differences with larger lip anatomy will be referred to as ethnic lips. This would apply to lips that are larger than the Caucasoid lip and more frequently treated with cosmetic lip reduction, or reduction cheiloplasty.

FIGURE 15-1 Typical lip size of a patient seeking lip reduction.

In the Caucasian patient, the upper lip constitutes a third of the total lip volume, and the lower lip constitutes about two-thirds, with a ratio of about 1 : 1.6^1,2 (Figure 15-2). African American lips are generally larger in all dimensions, and the upper and lower lip volumes are frequently nearly the same in many patients. Ethnic lips are also more protrusive, due in part to more soft-tissue mass. On average, chin and lip soft-tissue thickness is approximately 12 mm in Caucasians and 15 mm in African Americans.³ Vermilion height norms vary in different ethnicities: African American males have 13.3-mm upper lips and 13.2-mm lower lips, and African American females have 13.6-mm upper lips and 13.8-mm lower lips. North American Caucasian vermilion heights for upper and lower lips are 8.0 and 8.7 mm for males and 9.3 and 9.4 mm for females.^4,5 Normally there is a 0 to 3-mm intralabial gap between the lips in repose. Patients with a larger intralabial space may not be good surgical candidates.

FIGURE 15-2 Individual lip volume relative to total lip mass in a Caucasian female.

The importance of ruling out dentofacial deformities as contributing factors to macrocheilia cannot be overstressed, and orthodontic, oral, and maxillofacial consultation and a lateral cephalogram may be of assistance. Many African Americans exhibit a skeletal bimaxillary protrusion in which the angulation of maxillary and mandibular alveolar bone and teeth protrude anteriorly, influencing lip posture (Figure 15-3). If dentofacial abnormalities are not recognized, lip reduction may be contraindicated and worsen the cosmetic deformity by overly reducing lip size and exposing the dentofacial deformity. Microgenia can frequently accompany a bimaxillary protrusive profile, and the lack of chin prominence can make the lower lip appear larger.

FIGURE 15-3 A, Lateral cephalogram of a Caucasian male with a typical dentoskeletal relationship. B, Lateral cephalogram of an African American male with bimaxillary protrusion. Note the differences in alveolar, tooth, and lip relationships.

Esthetically, unusually large lips (like any body part) can make a person appear or feel unattractive. Adverse stereotypic characterizations historically amplified this trait (especially a “dangling” lower lip) and used it to demean those who possessed it. Reasons for seeking lip reduction may be motivated by more than psychological discomfort, however. Function can also be affected by very large lips, because they can make speaking and eating difficult in some cases and promote drooling in the case of abnormal orbicularis oris muscle tone.

Other ethnic patients presenting for lip reduction may not have abnormally large lips for their race but want to look more international. This is in the same vein as altering the eye shape, straightening the hair, tanning the skin, or getting lip filler. I refer to this as the cosmetic paradox in that people with small features want big ones, and people with big features want small ones. Beauty is truly in the eye of the beholder.

Lip Anatomy and Histology

The lips serve many functions: eating, drinking, speaking, mimetic animation, kissing, and serving as a valve for the terminal oral airway. Lips are among the most vascular structures on the face and are supplied by the superior and inferior labial branches of the facial artery as it branches from the external carotid artery. The labial artery lies in the posterior third of the lip at about the incisor level. The depth of this artery is an important landmark to keep in mind, but fortunately it is deep to most lip-reduction procedures.

The anatomy of the lip is very unique in that there is a triple transition from hair-bearing skin to vermilion tissue to oral mucosa. The hair-bearing skin terminates at the cutaneous/vermilion junction. The vermilion tissue consists of a very thin keratinized stratified squamous epithelium with extensive interdigitations with the underlying dermis (Figure 15-4). The vermilion is devoid of hair follicles, sweat glands, and sebaceous glands (although they may be sparsely present). The lack of sebaceous glands causes the vermilion to dry and crack, and hence the lips must remain moistened with saliva. The vermilion derives its color from the rich vascular plexus in the underlying dermis. This area is also highly sensitive, owing to its rich sensory innervation.

FIGURE 15-4 Vermilion portion of the lip consists of a thin, keratinized, stratified squamous epithelium (E) that extensively interdigitates with the underlying dermis (D).

(From Applebaum E, Lamm A, Moss-Salentijn L: Orofacial histology and embryology: a visual integration, Philadelphia, 1972, FA Davis.)

The thin, keratinized stratified squamous epithelium of the exposed vermilion transitions into a thick, nonkeratinized stratified squamous epithelium and becomes the intraoral mucosa (Figure 15-5). Under this thicker epithelium lies a submucosa containing numerous accessory salivary glands, including serous, mucous, and mixed seromucous glands.

FIGURE 15-5 Facial skin surrounding the lips contains hair follicles and sweat and sebaceous glands (A). The vermilion portion of the lip consists of thin, keratinized, stratified squamous epithelium (B) and transitions to the thick, nonkeratinized, stratified squamous epithelium of the oral mucosa (C). The submucosa of the intraoral mucosa contains numerous minor salivary glands (D). The orbicularis oris muscle is seen underlying these structures and constitutes the bulk of the lip (E). The vermilion is almost in contact with the orbicularis oris muscle anteriorly.

(From Applebaum E, Lamm A, Moss-Salentijn L: Orofacial histology and embryology: a visual integration, Philadelphia, 1972, FA Davis.)

The bulk of the lip volume is made up of the circumoral orbicularis oris muscle, which blends laterally into the complex modiolus, a convergence of the perioral mimetic muscles. The orbicularis muscle lies more to the posterior region of the lip, curls over the vermilion surface, and ends at the vermilion/cutaneous junction.(Figure 15-6).

FIGURE 15-6 Transverse section through the lower lip shows the dermis (D), fat (F), orbicularis oris muscle (OOM), vermilion (V), and oral mucosa (M). Note the orbicularis muscle is situated closer to the oral surface of the lip than the facial surface and also terminates as it curves around the vermilion cutaneous junction.

Lip-Reduction Procedure