ORIGINAL ARTICLE An Anatomical Approach to Glabellar Rhytids Michael R. Macdonald, MD; Jeffrey H. Spiegel, MD; Raymond B. Raven, MD; Sheldon S. Kabaker, MD; Corey S. Maas, MD Objective: To identify surface landmarks that can serve frontalis, and procerus muscles. as reference points to the underlying musculature in the treatment of glabellar rhytids. Conclusions: The information gained here may be ap- plied to the pharmacological or surgical treatment of gla- Methods: Fifty cadaver hemibrows were dissected to bellar rhytids. Knowledge of the frequent location of the assess the location, disposition, and relationships of muscles involved, relative to easily identifiable surface the brow muscles, along with their variations at each landmarks, allows a more precise approach. of several consistent locations. Particular attention was paid to the corrugator supercilii, frontal belly of the Arch Otolaryngol Head Neck Surg. 1998;124:1315-1320 HE GLABELLA occupies a the skin and factors associated with pho- relatively central position in toaging contribute to rhytid formation but the face and therefore eas- play a much less important role. ily attracts the attention of A variety of direct surgical ap- patients and their observ- proaches have been used for the eradica- Ters. Rhytids in this region, which range tion of glabellar rhytids since the 1920s. from fine lines to deep furrows, may re- This type of procedure allows direct visu- sult in the patient being incorrectly seen alization of the muscles to defunction or as angry, anxious, fatigued, fearful, or of excise them.3,4 The coronal lift has fluc- advanced age. Most commonly, glabellar tuated in popularity during the years.5,6 For rhytids are dynamic in nature. These hy- a long time, it was the only approach for perfunctional lines are a result of the pull elevation of the eyebrows, as well as cor- on the skin by the underlying facial mus- rection of the vertical and horizontal culature.1 This is in contrast to facial wrinkles in the glabella. Suspensive forces wrinkles in other areas, which result from from the forehead lift contributed to mak- age-induced changes in the collagen of the ing the glabellar area smoother, but muscle dermis. While the latter are frequently se- ablation was found to be essential. How- quelae of sun damage and aging in an older ever, patients without brow ptosis or fore- population, hyperfunctional glabellar lines head rhytids, who do not need or want a may be seen in younger patients, aged 20 brow lift, are often reluctant to agree to a to 50 years. coronal incision with its attendant scar- From the Division of Head and Individuals present with different pat- ring, morbidity, and recovery time. Neck Surgery, Department of terns of rhytid formation according to their Postsurgical patients are occasion- Surgery, Alameda County habits of facial expression and resting fa- ally able to contract residual corrugator or Medical Center, Oakland, Calif cial posture. The vertically oriented pro- procerus muscles, either in the early post- (Dr Macdonald); and Division cerus muscle is thought to make the great- operative period7 or within 3 to 4 months.8 of Head and Neck Surgery est contribution to the formation of This produces either a recurrence of the (Drs Spiegel and Raven), horizontal glabellar furrows, while the cor- initial complaint or a localized hornlike Aesthetic Facial Plastic Surgery rugator supercilii muscles produce the ver- prominence along the eyebrow that may Medical Clinic (Dr Kabaker), tical rhytids in this region. There may be be caused by the formation of a scar tis- and Division of Facial Plastic some contribution from a muscle identi- sue “bridge” between divided muscle seg- and Reconstructive Surgery 2 (Drs Kabaker and Maas), fied as the depressor supercilii, but de- ments. Alternatively, this may result from Department of Otolaryngology, scriptions of this muscle are few, bring- incomplete resection or transection of the University of California, ing its existence as a distinct entity into involved muscle groups. In response to this San Francisco. some question. The elastic properties of situation, more direct, limited surgical ap- ARCH OTOLARYNGOL HEAD NECK SURG/ VOL 124, DEC 1998 1315 ©1998 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/25/2021 MATERIALS AND METHODS Twenty-six cadavers were selected at random from the University of California at San Francisco Depart- ment of Anatomy Laboratory. There were 12 males and 14 females. Cadavers had undergone preserva- tion in the standard method and had had no previ- ous dissection of the head and neck. Complete dis- section of the glabellar region of the first female cadaver was carried out to confirm the relationships between the regional muscle groups. Each remain- ing cadaver provided 2 sets of brow musculature, thus providing 50 hemibrows for evaluation. Methylene blue was used to mark each cadaver Figure 1. Methylene blue markings before cadaveric dissection. along parallel sagittal planes through the midline of the nasal dorsum, the plane of the medial canthus, the plane of the midpupillary lines, and the plane of the lateral canthus (Figure 1). Incisions were made with a sharp No. 10 blade scalpel along these demarcated planes from skin to frontal periosteum (Figure 2). Dissections and measurements were done by a single prosector (M.R.M.) who was blinded to the accumulating results. Measurements were made by means of a steel caliper and steel ruler in millime- ters and included the following: corrugator super- cilii depth from skin; corrugator supercilii muscle belly thickness; frontalis muscle depth from skin; procerus muscle length; and procerus muscle depth from skin. The measurements related to the corru- gator and frontalis were taken at each of 4 locations (if present): midline, medial canthus, midpupillary Figure 2. Incisions made from skin to frontal periosteum, demonstrating line, and lateral canthus. The procerus muscle was tranverse section of underlying musculature. measured in the midline only. Additionally, the position of the predominant bulk of corrugator polytef, and autologous fat, have been used to lessen the muscle relative to a transverse line through the eye- 10,11 brow was assessed at the plane of the medial can- cosmetic deformity. These treatments do not ad- thus. Random specimens were reevaluated to dress the underlying facial musculature that produces the ensure internal consistency of measurement. Data functional lines. were recorded in preconstructed data tables. Once Botulinum toxin type A (Botox; Allergan Inc, Irv- the measurements were completed, the brow mus- ine, Calif) is a neuromuscular blocking agent that in- culature was dissected to make qualitative observa- duces a flaccid paralysis when injected into striated tions about the relative muscle orientation, posi- muscles.12 This toxin was first used in the 1970s in the tion, origins, and insertions. treatment of strabismus.13 In the 1980s, its use was ex- Statistical analysis of muscle measurements re- panded to the treatment of other facial dystonias, such lied on Student t test (2-tailed) for individual samples. as blepharospasm, hemifacial spasm, and oromandibu- Any missing data were pairwise deleted. In addition 14-16 to comparison among measurements within each cat- lar dystonia. More recently, its use in the treatment egory, measurements in males and females were com- of hyperfunctional lines of the face has been introduced pared across each category. Qualitative observa- as a simple, noninvasive alternative to surgery or fill- tions were, of course, not subjected to statistical ers.17,18 Carruthers and Carruthers17 first advocated its use analysis. However, descriptive trends regarding muscle in the treatment of glabellar frown lines in 1992. This size and position were observed. method has been effective in producing excellent tem- porary results. However, application of botulinum toxin to this area is still in its relative infancy, with precise dos- ing and administration techniques still under active in- proaches have been introduced. Endoscopic techniques vestigation. that use limited hairline incisions and transpalpebral ap- The results of medical and surgical approaches proaches are now advocated for excision of the corruga- have been varied in terms of initial effectiveness and tor or transection of the procerus.8 duration of action. After surgical resection of a portion Other attempts at correction of rhytids in this re- of the involved muscles, a scar may bridge the gap dur- gion have included direct excision, leaving unsightly scars ing the healing process so that reanimation occurs. or abnormal facial motion.9 Alternatively, tissue “fill- Alternatively, the muscle groups that cause the rhytids ers,” such as silicone, collagen, suture material, fibrin, may be incompletely resected. Similarly, under normal ARCH OTOLARYNGOL HEAD NECK SURG/ VOL 124, DEC 1998 1316 ©1998 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/25/2021 6 Males Females 5 4 3 2 Corrugator Supercilii Depth, mm Corrugator Supercilii 1 0 Midline Medial Canthus Midpupil Lateral Canthus Figure 3. Initial dissection was performed to identify the relationship Figure 5. Average findings for corrugator depth. between the various muscles in the glabellar region. Here, scissors are passed deep to the corrugator supercilii. 30 3.0 Males Females 25 2.5 20 2.0 15 1.5 No. of Hemibrows 10 1.0 5 Corrugator Supercilii Thickness, mm Corrugator Supercilii 0.5 0 0 Below Midline Position Above Midline Medial Canthus Midpupil Lateral Canthus Figure 6. Corrugator position relative to a transverse line drawn through the Figure 4. Average findings for corrugator thickness. midhorizontal eyebrow. circumstances, initial botulinum toxin treatment may RESULTS last from 3 to 6 months.17-20 Failure of botulinum toxin therapy or short duration of action may occur despite Initial dissection of the glabella, to establish the relation- the use of electromyographic (EMG) localization of the ships between the various muscles in this region, is dem- muscle.