F A C I A L P L A S T I CS U R G E R Y C L I N I C S

O F N O R T H A M E R I C A

Facial Plast Surg Clin N Am 15 (2007) 403–407

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Anatomic Considerations, Analysis,and the Aging Process of the PerioralRegionStephen W. Perkins, MDa,b,*, Henry Daniel Sandel IV, MDa

- Superficial anatomy and perioral analysis- Upper and lower lips- The aging process- Anatomic considerations for treatment

Sensory innervation and anesthesiaBlood supply

- Summary- References

Rejuvenation of the aging face encompasses vari-ous different procedures tailored to address specificproblems and characteristics of the face. The perio-ral region is an important aspect of this rejuvena-tion effort. It has certain anatomic characteristicsthat make it unique and responsive to differenttypes of treatments, including surgery, soft tissuefillers, laser, and chemical peeling. An understand-ing of the structural anatomy, relationships to otherfacial units, attractiveness, and analysis of the agingprocess will help the surgeon select appropriate andlong-lasting treatments.

Superficial anatomy and perioral analysis

On frontal view, the face can be divided into verticalfifths and horizontal thirds [1]. The perioral regioncan be defined as the lower one third of the faceextending laterally to encompass the middle threefifths of the face (Fig. 1). It is bounded by thesubnasale and cheek–lip groves superiorly and thementum inferiorly. The lower one third of the facecan be further divided into thirds with the upperone third, including the upper lip, and the lowertwo thirds, including the lower lip and chin [2].

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The oral commissure should lie within a verticalplane drawn from the medial limbus of the iris.The lips should meet on occlusion, and a 2- to 3-mminterlabial gap can be present on repose. A fewmillimeters show of the upper incisors may also bepresent, but no more than two thirds show whilesmiling. Fig. 2 describes commonly used referencepoints on soft tissue analysis.

On profile view, the upper lip should extend 2to 3 mm beyond the lower lip. Some authorshave measured this protrusion in relation to a planedrawn from the subnasale to the pogonion [3].Legan and Burnstone [3] found that the anterior-most point of the upper lip should be approxi-mately 3.5 mm from this line, and that of thelower lip should be 2.2 mm (Fig. 3). Others haveused the facial plane, a line from the glabella tothe pogonion, to note relationships in the perioralregion. Practically, these measurements are of littleimportance because of differences among racesand aesthetic ideals. The lips are also affected bythe skeletal and dental support underlying them.Therefore, a balance must be found when consider-ing soft tissue analysis in relation to the remainderof the face.

a Meridian Plastic Surgeons, 170 West 106th Street, Indianapolis, IN 46290, USAb Department of Otolaryngology-Head and Neck Surgery, Indiana University School of Medicine,Indianapolis, IN, USA* Corresponding author. Meridian Plastic Surgeons, 170 West 106th Street, Indianapolis, IN 46290.E-mail address: sperkski@aol.com (S.W. Perkins).

ts reserved. doi:10.1016/j.fsc.2007.08.006

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The chin extends from the mentolabial sulcus tothe menton. Its position can be assessed by a linedrawn vertically from the lower lip vermillion bor-der when the patient is in the Frankfort horizontalplane (Fig. 4). The pogonion should be at this linein men and up to a few millimeters anterior to thisline in women [4]. The depth of the mentolabialcrease should also be around 4 mm. A vertical chindeficiency is noted when the ratio of subnasale–stomion to stomion–menton is greater than 1:2. An-other method of determining projection of the chinis the zero-meridian method. A line dropped per-pendicular to the Frankfort horizontal plane fromthe nasion should reach the pogonion exactly [5].

This discussion should serve as a basis for facialanalysis and preoperative planning. These recom-mendations are merely guidelines and should onlybe considered along with sound clinical judgment.Also, analysis of the perioral region presumes thata normal dental–skeletal relationship exists. Abnor-malities such as malocclusion with retrognathia andvertical maxillary excess or deficiency are importantto recognize. These patients may require orthog-nathic surgery, which is beyond the scope of thisdiscussion.

Fig. 1. The face is divided into vertical thirds. The infe-rior one third can be further divided by the height ofthe upper lip compared with the lower lip and chin.

Upper and lower lips

The structure and shape of the upper lip is derivedfrom the fusion of its embryologic precursors.Near the end of the fourth embryonic week, the firstpair of pharyngeal arches, derived from neural crestcells, develops into facial prominences. The maxil-lary prominence is found laterally between thenasal placodes and the mandibular arch. Over thenext few weeks, the paired maxillary prominencesmigrate medially to approximate the paired medialnasal prominences. This fusion forms the upper lip.The fused medial nasal prominences form the phil-trum, medial upper lip, nasal tip, and columella.The remaining maxillary prominence forms thelateral portion of the upper lip and cheeks.

An esthetically pleasing upper lip will possessa soft M arch known as Cupid’s bow. Its apical por-tions meet the inferior aspect of the philtral ridges[6]. The upper lip may meet the lower lip in repose,with or without show of the central incisors. Thelower lip generally has more vermillion show andfullness than the upper lip. However, on profile

Fig. 2. Soft tissue reference points. gl, glabella; Li,lower lip vermillion border; Ls, upper lip vermillionborder; n, nasion; nt, nasal tip; sn, subnasale; ss, subspi-nale; sto, stomion; sm, submentale; pog, pogonion;m, mentum.

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view it is more posteriorly positioned than theupper lip. The lower lip is formed by the fusion ofthe paired mandibular prominences. This simplerprocess provides the uniform shape of the lower lip.

The vermillion is separated from the skin by thewhite roll of the vermillion border (Fig. 5). Animportant point when surgically repairing the lipedges is that continuity of this border is inherentlyobvious to an observer. A step or malalignment ofthe white roll, even by as little as 1 mm, is notice-able. The lip vermillion then curves posteroinfer-iorly toward the red line, the demarcated area thatseparates the dry portion of the lip visible on frontalview from the wet inner mucosal surface. The lipvermillion does not possess minor salivary glands,in contrast to the ‘‘wet’’ or buccal mucosal surfaceof the lip [7].

The aging process

From infancy, lips have excellent definition andobvious landmarks formed from the fusion of thefacial placodes. As puberty is reached, the lipsbecome fuller because of the hypertrophy of the or-bicularis muscle and glandular components. Grad-ually, they lose definition as a person ages, and the

Fig. 3. Legan and Burnstone measurements of upperand lower lip projection.

lips tend to become flatter. Their ratios change asthe upper lip elongates. Cupid’s bow is lost andthe oral commissures descend (Fig. 6).

Many factors can predispose a person to prema-ture aging, such as heredity and the size and fullnessof the lips in youth. Other factors, such as sunexposure and cigarette smoking, can advance thisprocess [8]. As the skin thins and the supportingorbicularis muscle atrophies, vertical rhytids de-velop at or above the vermillion border. Fullness,procumbency, and definition are lost. Laterally, as

Fig. 4. Normal chin position in relation to a verticalline drawn from the lower lip vermillion border (Vi).The pogonion (pog) should approximate this line.

Fig. 5. Anatomy of the lip vermillion.

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the oral commissure descends and the cheek softtissue loses support, marionette lines becomeprominent.

The cheek–lip grooves (nasolabial folds or melo-labial folds) are formed by the tightly adherent skinof the upper lip to the orbicularis oris muscle andfascia opposed to the loosely adherent skin andthicker subdermal fat of the cheek [9]. It extendsfrom the nasal ala to the modiolus, separating theaesthetic unit of the cheek from the perioral region.As a person ages, the malar fat pad descendsbecause of the weakening of the malar and orbitalligaments. This area overlaps medially and inferi-orly over the more firmly attached ligaments ofthe cheek–lip groove to create a fold. Authors

Fig. 6. (Top) Youthful lips. (Middle) Ideal lips. (Bottom)Aging lips.

have suggested various classifications of this groove,which may aid in the selection of the best treatmentoption [5]. Dermal fillers have evolved to treat moresuperficial grooves, whereas soft tissue or alloplasticimplants may play a role in more defined, deepcheek–lip grooves [10].

The aging process produces further changes mostnoticeable along the mandible. Loss of subcutane-ous fat tends to create a prejowl sulcus betweenthe chin and sagging lower cheek, and anterior tothe masseter muscle. Attachments of the chin softtissue to the symphysis of the mandible can alsoweaken, creating a ‘‘witches chin’’ appearance.

Anatomic considerations for treatment

Sensory innervation and anesthesia

The innervation to the perioral region comesmainly from the trigeminal and facial nerves. Thesecond (V2) and third (V3) divisions of the trigem-inal nerve supply sensory information overlying theregion of the maxilla and mandible, respectively.Anesthetizing the upper lip, nasal ala, cheek–lipgrooves, and malar prominence requires treatmentof V2 exiting the inferior orbital foramen. A needleplaced under the lip, directed from the alveolarprominence of the first maxillary premolar towardthe pupil, and infiltrated at a depth of approxi-mately 4 to 5 cm onto bone will capture this nerve(Fig. 7). Perforators of V2 exiting the inferolateralmaxilla must also be anesthetized with local infil-tration in the gingivolabial sulcus.

If the oral commissure, posterior cheek, mario-nette lines, and lower lip require anesthesia, thenthe third division of the trigeminal nerve must betreated. V3 not only sends a branch through themandible and inferior alveolar nerve but also hasa superficial branch called the buccal nerve. Thisnerve sends sensory information from the posteriorcheek beyond the masseter muscle and the regionlateral and inferior to the oral commissure andlower mandible. The lower lip has sensory innerva-tion from the inferior alveolar nerve that exits theparasymphysis at the mental foramen. This nervecan be found beneath the second mandibular pre-molar midway between the alveolar prominenceand the lower border of the mandible. A bilateralmental foramen nerve block will give adequateanesthesia to the entire lower lip but may not treatthe region lateral to the oral commissure.

Blood supply

Blood supply to the perioral region comes mostlyfrom the facial artery. The facial artery arises fromthe external carotid artery and enters the face ata point near the anterior inferior portion of themasseter muscle. It lies just on top of the mandible

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and enters the perioral region parallel to the cheek–lip groove. As it travels through the buccal fat, itbranches superficially near the modiolus into theinferior and superior labial arteries. The buccal ar-tery branches posteriorly and deep to anastomosewith the internal maxillary artery. The distal portionof the facial artery becomes the angular artery,which extends along the pyriform aperture andgives off branches, including the lateral nasal arterylocated superior to the nasal ala. Additional mid-face arteries include the inferior orbital artery andtransverse facial artery.

Fig. 7. The infraorbital foramen can be found ona line drawn from the first maxillary premolar alveo-lar prominence toward the pupil at a depth ofapproximately 4 to 5 cm.

Other branches to the lower lip include the sub-mental artery and the mental branch of the inferioralveolar artery.

Summary

As with the remainder of the face, analysis of theperioral region and an understanding of the agingprocess help guide surgeons to provide appropriateand balanced rejuvenation treatments. Althoughthis article describes precise relationships and mea-surements, they should not substitute for soundclinical judgment and a good esthetic sense.

References

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[3] Legan H, Burnstone C. Soft-tissue cephalometricanalysis for orthognathic surgery. J Oral Surg1980;38:744–51.

[4] Calhoun KH, Stambaugh KI. Facial analysisand preoperative evaluation. In: Bailey BJ,Johnson JT, et al, editors. Head and neck sur-gery—otolaryngology. Philadelphia: LippincottWilliam and Wilkins; 2006. p. 2481–97.

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[9] Karsan N, Ellis DAF. The lip-cheek groove. ArchFacial Plast Surg 2006;8:324–8.

[10] Cheng JT, Perkins SW, Hamilton MM. Perioralrejuvenation. Facial Plast Surg Clin N Am 2000;8(2):223–33.