Anatomical connections among the depressor supercilii, levator labii superioris alaeque nasi, and inferior fibers of orbicularis oculi: Implications for variation in human facial expressions

Anatomical considerations for thread-based brow lifting and wrinkle treatment

This review explores the anatomical considerations and technical aspects of thread lifting for the forehead and eyebrow, focusing on the relationships between vascular structures, muscular anatomy, and age-related changes in the forehead-eyebrow complex. It highlights the critical importance of understanding neurovascular pathways, particularly the supratrochlear and supraorbital vessels, as well as the appropriate thread placement techniques necessary for optimal outcomes. The review demonstrates that I-shaped threads, when placed beneath the frontalis muscle, provide a safer and equally effective alternative to traditional U-shaped designs. Additionally, the review emphasizes the significance of preoperative assessment, especially the evaluation of tissue mobility and adhesion patterns, in predicting procedural success. The review concludes that combining thread lifting with volumising monofilaments offers a comprehensive approach to rejuvenating the forehead-glabellar region, while minimizing the risk of complications. This study's clinical impact lies in its potential to enhance both the safety and efficacy of thread lifting procedures, offering practitioners a refined technique for esthetic rejuvenation of the forehead and eyebrow complex.

Dynamic Periocular Wrinkle Patterns: An Anatomical Study on Young Adults

BACKGROUND

Aging causes facial wrinkles, especially dynamic wrinkles related to mimic movements, predisposing areas to static wrinkles from a young age, notably in the periorbital region. This study aims to analyze dynamic wrinkle patterns on periorbital skin during mimic movements in healthy young adults to identify wrinkle precursor regions.

METHODS

Dynamic periorbital wrinkle patterns were analyzed in 184 healthy adults (93 females, 91 males) aged 18-24 years. Standardized facial photographs were taken at rest and during various mimic movements. The periorbital region was divided into superior, inferior, lateral, and medial subregions; wrinkle patterns were classified and analyzed. Interobserver and intraobserver reliability were assessed.

RESULTS

In the upper periorbital region, the most common wrinkle pattern was oblique lines extending from the medial and lateral canthus to the upper corners (Type 3, 56%). Inferiorly, the most common pattern was a linear wave from the lateral canthus to the lateral margin (Type 3, 25.5%). Medially, no specific pattern (Type 6, 33.2%) and an arrowhead-like motif directed toward the medial canthus (Type 2, 20.7%) were prevalent. Laterally, radial waves extending from the lateral canthus to the lateral brow tip were most common (Type 1, 34.8%). The absence of a distinct wrinkle pattern in the medial region was more common in men than in women (48.4% vs. 17.6%). Males were more likely to have wrinkle patterns consisting of oblique short lines in the inferolateral direction in the inferior region (Type 2, 31.2%). Miniature crow's feet-like wrinkles were more common in females.

CONCLUSION

This study presents a new classification of dynamic wrinkle patterns in the periorbital region in young adults, highlighting sex differences.

Resolving the Controversy Surrounding the Function of the Corrugator Supercilii Muscle

INTRODUCTION

The corrugator supercilii muscle (CSM) has traditionally been recognized as a primary depressor of the eyebrows, playing a key role in expressing negative emotions and contributing to the formation of glabellar lines. However, recent studies indicate that the CSM may exhibit movements contrary to those previously documented, suggesting a more complex functional role. This research re-evaluates the anatomical and functional roles of the CSM and discusses their implications for botulinum toxin treatments.

MATERIAL AND METHODS

A prospective, intrapersonal comparative, and split-face study was conducted over a five-year period, from January 6, 2019, to January 6, 2024, involving 298 patients who underwent botulinum toxin injections. The study divided participants into seven groups, each targeting specific anatomical areas of the CSM and associated muscles. Injection techniques were varied to assess their impact on brow dynamics, with outcomes measured by changes in eyebrow position and expression lines.

RESULTS

The study demonstrated that targeting specific portions of the CSM and depressor supercilii muscle (DSM) leads to distinct outcomes in brow elevation and the reduction of expression lines. However, this approach was also frequently associated with the development of omega-shaped wrinkles. Split-face evaluations further validated that the modified injection techniques achieved superior eyebrow elevation compared to traditional methods.

CONCLUSION

This study challenges the traditional view of the CSM as primarily a brow depressor, highlighting its role in medial brow elevation. These findings underscore the need for a nuanced approach in esthetic medicine, particularly in botulinum toxin injections, to achieve balanced and natural facial expressions. Understanding the full range of CSM functions is crucial for optimizing esthetic outcomes and enhancing patient satisfaction.

LEVEL OF EVIDENCE II

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Selective midfacial neurectomy for postparalytic facial nerve syndrome

Chemodenervation with botulinum A toxin and neuromuscular retraining therapy are commonly performed as first-line treatments for postparalytic facial nerve syndrome (PFS). However, their effects are temporary, and side effects typically develop. Currently available selective neurectomy approaches are limited by variations in the anatomy of the peripheral branches of the facial nerve and the ability to reduce perioral synkinesis, but not periocular synkinesis. We devised a novel selective midfacial neurectomy for PFS that considers anatomical characteristics and is effective for both periocular and perioral synkinesis. In our approach, the facial flap was elevated subcutaneously, and facial nerve branches were identified at the anterior margin of the parotid gland. Using intraoperative nerve stimulation, the thin cranial zygomatic branches that innervate the lateral portion of the orbicularis oculi muscle and the buccal branches that innervate the orbicularis oris muscle independently were preserved. The thick caudal zygomatic branch and its communicating branch with the cranial buccal branches, which simultaneously and strongly contract both the periocular and perioral mimetic muscles, especially around the medial upper and lower eyelids, were selectively excised. From March 2021 to September 2022, selective midfacial neurectomy was performed in five patients with House-Brackman (HB) grade III-IV unilateral facial paralysis. With respect to the synkinesis score and palpebral fissure width ratio, statistically significant improvements were observed between the preoperative and 18-month postoperative values. Selective midfacial neurectomy is effective in treating patients with postparalytic facial nerve syndrome.

Anatomical etiology of bunny lines based on cadaveric dissection and ultrasonographic evaluation

Bunny lines are vertical and diagonal wrinkles attributed to contractions of the nasalis muscle. Common management involves botulinum toxin (BoNT) injections into wrinkles immediately below the nasal bridge. Here, we investigated the anatomical structures underneath bunny lines and their relationships with adjacent muscular structures. The area between the medial canthus and nasal dorsum was examined by ultrasonography in 13 adult volunteers (mean age, 29.4 years) and dissected in 39 cadavers. The findings consistently showed a non-muscular area (bunny triangle) between the borders of the procerus, nasalis, orbicularis oculi (OOc), and levator labii superioris alaeque nasi (LLSAN) muscles. The size and shape of the bunny triangle vary according to the width of the procerus and nasalis muscles. The muscles neighboring the bunny lines affect the thinning of the thin skin between the medial canthus and nasal dorsum. Our results indicate that conventional BoNT injection into bunny line wrinkles is likely to target connective tissue rather than a muscle, potentially producing suboptimal results. Therefore, the BoNT injection points probably need to target the borders of the procerus, nasalis, OOc, and LLSAN muscles to be most efficient.

Advanced Injection of Botulinum Toxin in the Nasal Muscles: A Novel Dynamic Change in Facial Expression

BACKGROUND

Among the nasal muscles, the levator labii superior alaeque nasi (LLSAN) acts as a transitional muscle that conjugates with other nasal and perinasal muscles. Thus, when treating the nasal region with Botulinum toxin (BTX), it is important to understand local nasal muscular dynamics and how they can influence the muscular dynamics of the entire face.

METHODS

This is a retrospective analysis of cases treated by an injection pattern encompassing the face, including nasal muscles. Photographs were taken at rest and during motion (frontal and oblique views), before and after treatment.

RESULTS

A total of 227 patients have been treated in the last 18 months with the following results: eyebrow tail lifting, softness of crow's feet, improvement of the drooping of the tip of the nose, and shortening of the lip philtrum when smiling. We present cases illustrating the use of this approach.

CONCLUSIONS

Treating the facial muscles globally (including the frontal, corrugators, procerus, orbicularis oculi, platysma, DAO, and nasal muscles) can improve the smile and facial expressions. This is believed to occur because the elevated portion of the upper lip muscle becomes stronger as the nasal part of the LLSAN is paralyzed.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Mapping the Vascular and Muscular Topography of the Glabellar Region: Implication for Improving Safety and Efficacy of the Glabellar Injections

BACKGROUND

Botulinum neurotoxin (BoNT) and filler injections into the highly vascularized glabellar region for aesthetical purposes are extremely common. Injections into the glabellar region without precise anatomical knowledge of its vascular and muscular topography may pose the risk of severe complications.

OBJECTIVES

We aimed to improve the safety and efficacy of the glabellar injections by mapping the regional muscles and vasculature in relation to the medial canthus and the defined reference lines.

METHODS

Meticulous dissection was performed to reveal glabellar region muscles and arteries under surgical microscope, in 16 hemifaces of whom arteries are injected with red-dyed latex. Location of the angular artery (AA) along with its branches was noted in relation to glabellar muscles.

RESULTS

The AA was always located superficial to the levator labii superioris alaeque nasi muscle (LLSAN) and then coursed toward the medial canthus to anastomose with the supratrochlear artery deep to the origin of the depressor supercilii (DS). The AA gave subcutaneously located central and paracentral branches coursing close to the mid-face line in 14 out of 16 hemifaces. Variable muscular connections were also present between the LLSAN, the DS and the procerus (P) muscles. No arteries were detected at the base of the medial eyebrow to which the DS, the P, and the frontalis (F) inserted.

CONCLUSIONS

This study provides a detailed map of muscular and vascular anatomy of the glabellar region to facilitate safe and efficient filler and BoNT injections without complications.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Consensus Statement on the Use of Botulinum Neurotoxin in the Middle East

Background

Aesthetic minimally invasive procedures have become very popular and culturally acceptable among Middle Eastern populations. Botulinum neurotoxin type A (BoNTA) is a valuable treatment modality for many cosmetic as well as therapeutic indications. The presence of BoNTA in our toolkit has revolutionized the field of aesthetic medicine to the point where it is now one of the most commonly performed cosmetic procedures worldwide. This consensus considers popular on- and off-label BoNTA indications in the Middle East.

Methods

A multinational group of ten key opinion leaders, experts in facial plastic surgery and dermatology, convened the Middle East Aesthetics Consensus Group and reviewed the aesthetic applications of BoNTA. Recommendations and position statements were drafted based on the integration of the panel's clinical experience with published data, targeted to the practices implemented in the Middle Eastern and the global population.

Results

Guidance statements are presented covering Middle Eastern facial characteristics and beauty ideals, BoNTA characteristics, pre-operative counselling, treatment indications and anatomical considerations, off-label and special uses including high-dose recommendations, and post-treatment advice. Throughout, an evidence-based approach to selection of products and injection techniques is provided, supplemented by the experts' advice on injections dosages and placement.

Conclusion

This consensus reflects the knowledge and expertise of physicians practicing in the Middle East. The panel acknowledged the use of on-label indications and variability in the toxin formulations and immunogenicity and agreed upon a wide use of "off-label" indications.

"Untying the knot": The primitive orofacial muscle architecture in the gorilla (Gorilla gorilla) as a key to the evolution of hominin facial movement

The anatomical underpinnings of primate facial expressions are essential to exploring their evolution. Traditionally, it has been accepted that the primate face exhibits a "scala natura" morphocline, ranging from primitive to derived characteristics. At the primitive end, the face consists of undifferentiated muscular sheets, while at the derived end there is greater complexity with more muscles and insertion points. Among these, the role of the human modiolus ("knoten" in German) has been emphasized. Recent studies have challenged this view by revealing significant complexity in the faces of several non-human primates, thereby rejecting the linear notion of facial evolution. However, our knowledge of the facial architecture in gorillas, the second closest living relatives to modern humans, remains a significant gap in the literature. Here, we present new findings based on dissection and histological analysis of one gorilla craniofacial specimen, alongside 30 human hemifaces. Our results indicate that while the number and overall arrangement of facial muscles in the gorilla are comparable to those of chimpanzees and modern humans, several orofacial features distinguish the gorilla's anatomy from that of hominins. Among these are the absence of a modiolus, the continuity of muscular fibers over the region of the mouth corner, the flat (uncurving) sheet of the orbicularis oris muscle, and the insertion of direct labial tractors both anterior and posterior to it. Collectively, the anatomical characteristics observed in the gorilla suggest that the complex anatomy of the hominin face should be considered synapomorphic (shared-derived) within the Pan-Homo clade.

Variant muscle fibers connecting the orbicularis oculi to the orbicularis oris: case report

The orbicularis oculi (OOc) is a sphincteric muscle of the eyelids, whereas contraction of the orbicularis oris (OOr), another sphincteric muscle, causes narrowing of the lips. Facial muscle fibers normally blend with adjacent muscles. However, muscle fibers connecting the various facial muscles that have different actions and that are located at distant sites, such as the OOc and the OOr have been rarely reported. Herein, we report a rare case of connecting fibers between the inferior margin of the OOc and the OOr. These connecting fibers were blended with the OOr between the inserting fibers of the levator labii superioris and levator anguli oris. Contraction of such variant muscles might affect typical facial expressions.