Understanding the Shape of Forehead Lines
May 2017 | Volume 16 | Issue 5 | Original Article | 471 | Copyright © May 2017
Milad Moqadam,a Konstantin Frank,b Christina Handayan,a Mustafa Hakami,a Fahd Benslimane MD,c Robert H. Gotkin MD,d Neil S. Sadick MD,e and Sebastian Cotofana MD PhDf
aDepartment of Anatomy, Ross University School of Medicine, Roseau, Commonwealth of Dominica, West Indies bDepartment for Hand, Plastic and Aesthetic Surgery, Ludwig – Maximilian University Munich, Germany cClinique Benslimane, Casablanca, Morocco dPrivate Practice, New York, NY eWeill Medical College Cornell University, New York, NY fDepartment of Medical Education, Albany Medical College, Albany, NY
Abstract
Background: Individualized neuromodulator injections of the forehead are increasingly important to maximize patient safety and satisfaction and to yield the best aesthetic outcome. To assess the location of maximal muscle contraction, it would beneficial to relate the shape and location of the forehead lines to the morphology of the underlying frontalis muscle.
Materials and Methods: We investigated the shape of forehead lines and their relationship to the morphology of the underlying frontalis muscle using anatomic dissection in a sample of 31 human body donors, with a mean age at death of 77.2 ± 13.2 years (range, 47–93) of which n=29 (93.5%) were of Caucasian and n=2 (6.5%) of African-American ethnicity and of which n=16 (51.6%) were females (n=15 males; 48.4%).
Results: Horizontal forehead lines were classified into straight n=13 (41.9%) and wavy n=18 (58.1%) lines. The presence of wavy forehead lines (as compared to straight lines) was significantly related to the presence of a midline aponeurosis (r = 0.69; P less than 0.001) and to a greater muscle fascicle angle (12.67 ± 2.60° vs 10.18 ± 2.12°) (r = 0.47; P less than 0.001), but was not statistical significantly influenced by age, gender, or ethnicity (all P greater than 0.05).
Conclusion: According to the shape of the forehead lines, physicians can appreciate the morphology of the underlying frontalis muscle. This understanding will facilitate more accurate neuromodulator injections and a better aesthetic outcome. It may also result in decreased dosages and increased injection intervals for maximal patient safety.
Level of evidence: IV
J Drugs Dermatol. 2017;16(5):471-477.
INTRODUCTION
Neuromodulator injections have become the leading minimally invasive cosmetic procedure in the United States with an increase of 759% when compared to the year 2000.1 Of the 6,757,198 neuromodulator injections performed in the United States in 2015, 94% were performed in females – the most common ethnicity being Caucasian (76%) and the most frequent age group between 40-54 years.1Neuromodulator injections in the forehead offer predictable results,2 have few adverse effects,3 and are associated with a high degree of patient satisfaction.4 The ultimate effect of neuromodulators in the forehead is a temporary paralysis of the underlying frontalis muscle, an inability to contract the overlying skin, and a reduction or elimination of the horizontal forehead lines.5,6 According to the Global Aesthetic Consensus on neuromodulator uses,5 it is recommended to target muscles in areas where the excessive contraction is the primary cause of the changes seen in the overlying skin. Performed properly, this can result in decreased dosages and increased injection intervals. Additionally, it was recommended to recognize the influence of demographic characteristics, individual muscle anatomy, and muscle contraction pattern7,-11 in order to guide appropriate neuromodulator injections.12-15With respect to the frontalis muscle, one should be aware of the individual variations in shape, width, length, the presence or absence of a midline aponeurosis, muscle fascicle angle, and the synergistic influences of age, sex, and ethnicity on the formation of horizontal forehead lines when treating the forehead with neuromodulators. For the best aesthetic and most long-lasting result, it would be beneficial if one could correlate the shape of the forehead line contraction pattern to the anatomy of the underlying frontalis muscle. This would guide physicians to evaluate the sites of injection more effectively, the dosing of product, and to individualize the injections as compared to currently frequently used rigid and non-individualized application patterns. Therefore, the aim of the present study is to investigate the relationship between the shape of horizontal forehead lines and
