ARticle | boTulInuM ToxIn A | CoSMeTIC uSeS of onAboTulInuMToxIn A
in the lower face, neck and chest
in the final article of the series, Anthony V. Benedetto explains the functional anatomy, dosing, outcomes, and complications when treating this area with botulinum toxin A
A
ANTHONY V. BENEDETTO, DO, FACP is a Clinical Associate Professor of Dermatology at the Department of Dermatology, University of Pennsylvania School of Medicine. Dr Benedetto is the founder and medical director of the Dermatologic SurgiCenter in Philadelphia, PA and in Drexel Hill, PA, where he practices Mohs Surgery and Cosmetic and Procedural Dermatologic Surgery
email
avb@benedettoderm.com
KEYWORDS botulinum toxin A, injection, lower face, lips, melomental folds neck, décolletage
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nAtomic delineAtion of the lower face encompasses the perioral region, chin and jaw line. the orbicularis oris functions as a sphincter, providing a combination of levator and depressor movements to the upper and lower lips,
and the corners of the mouth. the remaining facial muscles comprise the levators of the upper lip and the depressors of the lower lip. these muscles open and close the mouth and perform essential buccal functions in unison with the orbicularis oris when eating, speaking and drinking. By contracting the orbicularis oris along with its levators and depressors in a particularly idiosyncratic manner, a person can deliberately or involuntarily express different emotions. In the lower face, fibres of the orbicularis oris interdigitate
with some, if not all, of the upper lip levators and lower lip depressors. As a result, the orbicularis oris can function as an antagonistic muscle and perform the opposite movement of either the levators and the depressors after they have moved in unison to separate or approximate the lips when opening or closing the mouth, as one does when puckering the lips to whistle or kiss. These subtle differences in the way the perioral muscles
operate play a significant role in devising a treatment plan with botulinum toxin A (the author uses onabotulinumtoxinA). As our injection techniques improve and our understanding of how the muscles in the lower face respond to treatment, it is becoming increasingly obvious that the lower face and neck should be treated as a defined, all‑encompassing unit.
Perioral lip lines and rhytides A full lip with a smooth and distinct border of the vermillion delineating it from the rest of the cutaneous lip is a hallmark of youth. With time and sun exposure, the lips become thin, flaccid, elongated and wrinkled, leaving an appearance of weariness, evidenced by wrinkles on the face and betrayed by perioral rhytides.
July 2011 |
prime-journal.com Static and dynamic wrinkling can be found around the
mouth appearing as vertical lip lines perpendicular to the vermillion border. Static wrinkles are caused not only by intrinsic ageing and photodamage, but are also precipitated by smoking 1
. Dynamic wrinkles are found in those who are
genetically predisposed and frequently pout and purse their lips, whether deliberately or involuntarily. Repeated purse string‑like movements of the orbicularis oris exaggerate and intensify the dynamic perioral lines. Men are not usually in the habit of pursing or puckering their lips, and are ‘blessed’ with facial hair that may help preclude the fine infolding and wrinkling of facial and labial skin. There are many causes for these perioral lines, which
can also be manifested as static wrinkling. Static wrinkles can be the result of identifiable causes (e.g. environmental exposure), and unknown causes (e.g. genetics, gender differences, intrinsic soft tissue characteristics). Much of the static wrinkling can be reduced by invasive surgical procedures. Static wrinkling can also be reduced by non‑invasive procedures, such as injections of synthetic soft tissue fillers or autologous fat. Static wrinkles can be easily distinguished from dynamic
wrinkles by asking a person to purse his/her lips. If there are rhytides present in the lips before pursing, and there is minimal change or intensification of these wrinkles with movement, then the perioral rhytides are primarily static and generally not reducible by botulinum toxin A (Figure 1). If the wrinkles accentuate and deepen with lip movement and puckering regardless of age, then these are dynamic wrinkles and can be diminished with injections of botulinum toxin A.
Functional anatomy The shape of the mouth and position of the lips are controlled by interlacing and decussating bundles of facial muscles. These include the various levators of the upper lip (i.e. levator labii superioris alaeque nasi, levator labii superioris, zygomaticus major et minor, levator anguli oris, and risorius), various depressors of the lower lip (i.e.
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