Platysma and the cervical superficial musculoaponeurotic system — Comparative analysis of facial crease and platysmal band development

The Platysma Contraction Pattern in Healthy Adults: A Vector Analysis Study

BACKGROUND

The platysma muscle's role in lower face dynamics is complex. Multiple insertion points to soft-tissue structures at various levels in the lower face create a multifaceted contraction pattern. To avoid adverse effects in cosmetic procedures when targeting the platysma, its anatomy and physiology must be understood. Clinical observations hint at a bidirectional contraction pattern.

METHODS

Eighteen healthy volunteers (13 women and five men) with a mean age of 44.2 ± 10.1 years were enrolled. Skin displacement vector analysis was used on maximal platysma contraction to characterize and calculate the movement of the neck and lower face skin.

RESULTS

In all of the participants, a bidirectional movement of the skin was observed: the skin of the lower face and inferior to the jawline moved caudally, whereas the skin of the lower neck moved cephalad. Both movements converged at a line situated at 54% ± 10% and 55% ± 8% of the length between the clavicle and the inferior base of the ear lobe in men and women, respectively ( P = 0.70).

CONCLUSIONS

The platysma is a bidirectional muscle with a line of convergence. Whereas the superior portion acts as lip depressor, the lower portion elevates the skin of the upper chest and lower neck. This transition can explain some of the clinically observed adverse effects of neuromodulation of the neck area. It can potentially direct neuromodulation injections to focus above the convergence line to better address lower face descent.

Histomorphological analysis of the superficial musculoaponeurotic system in Macaca mulatta species

INTRODUCTION

The superficial musculoaponeurotic system (SMAS) is a well described facial functional unit in humans. SMAS connects mimic musculature to the skin having many implication in facial mimic expression. One of the various morphological and physiological analogies in human and Macaca mulatta species is the facial mimic. The present study analyzed Macaca mulatta species SMAS morphology and its facial topographical differences and compared this with human SMAS tissue morphology.

MATERIAL AND METHODS

Macaca mulatta full-graft tissue blocks of skin, subcutaneous tissue and mimic muscles from five topographical different facial regions (Regio Temporalis, Regio Buccalis, Regio Infraorbitalis, Regio Angulus Oris and Regio Mandibularis) were collected postmortem from eight individuals (n = 8) at the German Primate Center, Leibniz Institute for Primate Research in Göttingen (DPZ) and studied histologically. Haematoxylin-eosin and azan stained histological serial sections of full-graft tissue blocks were analyzed and SMAS topographical differences evaluated.

RESULTS

SMAS typical tissue morphology was recognized in all Macaca mulatta histological serial sections (n = 780). Regio Infraorbitalis Macaca mulatta SMAS (MmSMAS) morphology was similar to human infraorbital SMAS morphology (type I SMAS). Suborbicularis oculi fat pad was recognized in Macaca mulatta samples. Human type I similar SMAS morphology was demonstrated over Macaca mulatta Regio Temporalis and Regio Buccalis. Regio Angulus Oris and the cranial area of the Regio Mandibularis presented human type II similar SMAS morphology. Type IV MmSMAS was closely related to the parotid gland tissue presence. The cervical area of the Regio Mandibularis presented human type V similar SMAS morphology.

CONCLUSIONS

SMAS is a complex fibro-musculo-adipose tissue network and probably an important pivot in Macaca mulatta facial system supporting mimic expression. This study provided insights into MmSMAS typology and similarity with human SMAS tissue morphology.

Surgical Management of Platysma Bands: A Narrative Review of Evolving Concepts and Changing Techniques for Neck Rejuvenation

INTRODUCTION

Platysmal bands are an unappealing feature of the aging face. Incomplete understanding of anatomy and physiology of platysmal bands has led to a long period of flawed or incomplete treatment. This review aims to elucidate the correct study of platysmal bands along with the most recent surgical treatments.

MATERIALS AND METHODS

To identify all articles related to the topic of surgical management of platysmal bands, an extensive search was performed on PubMed and Medline databases for all articles related to platysmal bands from 1990 to 2023. The articles were then reviewed by 2 independent reviewers, and all relevant articles were selected. The search was narrowed down to clinical trials and cohort studies.

RESULTS

6130 articles were identified, of which 21 articles matched the inclusion criteria and were selected for the study totaling 2331 patients. Different surgical procedures were mentioned. Assessment of results was mostly subjective and done by the surgeon.

CONCLUSION

Composite platysma-skin flap repositioning as opposed to wide skin undermining with or without submental incisions is being gradually accepted as a valid approach, with closed platysma myotomy and platysma denervation emerging as effective less invasive surgical modalities. Nevertheless, merits of more extensive procedures involving wide skin undermining and anterior platysma plication must not be lightly forgotten.

LEVEL OF EVIDENCE III

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The Underappreciated Role of the Platysma Muscle in the Perioral Expressions in Young Adults

BACKGROUND

The platysma is involved in lower face movement, yet limited information on its functional role when making perioral expressions is available.

OBJECTIVES

The aim of this study was to use 3-dimensional (3D) photogrammetry to analyze platysma activity when making expressions.

METHODS

Standardized frontal-view 3D images were obtained from 54 volunteers. Three perioral expressions were analyzed: a full smile, mouth corner depression, and a grimace to show the lower teeth. Positive volume change in the "heat map" of the neck skin surface-determined by the superimposed image subtraction technique-served as a sensitive indicator of platysma contraction.

RESULTS

When making the 3 expressions, the proportions of platysma contraction were 42.6%, 75.9%, and 92.6%, respectively. The platysma worked as a more critical dynamic force than expected. In most smiles involving the platysma, its upper portion contracted. With the laterally downward traction on the lower lip increasing, the upper and lower portions of the platysma contracted together and formed muscular bands. The platysma contracted extensively in the other 2 expressions. In some cases, platysma bands were observed to form due to vigorous contraction of muscle fibers. In addition, the platysma was found to be highly functionally active in young individuals.

CONCLUSIONS

This study introduced a simple method that can sensitively identify the functional status of the platysma. The results showed the platysma's highly active function in perioral expressions in young adults. These findings may assist surgeons in personalized decision-making toward platysma muscle-weakening strategies and work as an objective tool for outcome evaluation.

LEVEL OF EVIDENCE: 4

Anatomy behind the Paramedian Platysmal Band: A Combined Cadaveric and Computed Tomographic Study

BACKGROUND

The muscular hypothesis explanation of the pathophysiology behind paramedian platysmal bands does not seem to provide a sufficient explanation for the clinical presentation of these platysmal bands in aged individuals with cervical soft-tissue laxity. The purpose of this study was to investigate the fascial relationships of the anterior neck to enhance appropriate surgical treatment.

METHODS

Retrospective analysis of computed tomographic scans of 50 Caucasian individuals (mean age, 55.84 ± 17.5 years) and anatomical dissections of 20 Caucasian and 10 Asian body donors (mean age, 75.88 ± 10.6 years) were conducted. Fascial adhesions were classified according to platysma fusion types, and platysma mobility was tested during dissection procedures.

RESULTS

Fusion between the left and right platysma muscles occurred in 64 percent in the suprahyoid region and in 20 percent at the thyroid cartilage, and in 16 percent, the platysma attached to the mandible without fusion. In the absence of muscular fibers, a fascial adhesion zone with limited mobility was observed where the superficial cervical fascia fused with the investing layer of the deep cervical fascia.

CONCLUSIONS

Muscular contraction of the platysma results in elevation of the most medial platysma muscle fibers, which are not attached in the fascial adhesion zone. The presence of a fatty layer deep to the platysma enables platysmal movement and anterior and inferior gliding of the skin and platysma when cervical soft-tissue laxity exists. Surgical treatments should include transection of the fascial adhesion; this could potentially prevent the recurrence of paramedian platysmal bands.

Immunohistochemical evidence of striated muscle cells within midfacial superficial musculoaponeurotic system

INTRODUCTION

The superficial musculoaponeurotic system (SMAS) is a controversial functional fibro-adipose layer that connects the mimic muscles to the skin and is involved in a variety of facial mimic expressions. The presence of muscle fibers within SMAS fibrous septa is hypothetical. The present study analyzed SMAS fibrous septa composition for the existence of striated muscle cells.

METHODS

Histological serial sections of the sample borders (n=107) of 19 in sano-resected and diagnosed cutaneous tumors of the midfacial region were investigated. Immunohistochemical (actin and myosin) and hematoxylin and eosin staining were performed to detect striated muscle cells in SMAS fibrous septa.

RESULTS

A fibro-neuro-musculo-vascular functional unit within SMAS fibrous septa was demonstrated. SMAS striated muscle cells were morphologically independent from preparotideal and periorbital mimic muscles. Intraseptal blood vessels draining the superficial and deep SMAS vascular system were described.

CONCLUSIONS

Striated muscle cells were demonstrated within SMAS fibrous septa. Nerve cells and vascular tissue together with the SMAS fibro-muscular meshwork demonstrated an autonomous operating functional unit that hypothetical modulated individual mimic expression contributing to the diversity of mimic expression. The SMAS develops with mimic muscle contractions as a synergetic effect during facial crease and fold formation processes.