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

A Comprehensive Ultrasound Investigation of Lower Facial and Neck Structure

BACKGROUND

The jawline and neck significantly influence facial aesthetics. Botulinum toxin and filler are highly favored as minimally invasive jawline rejuvenation procedures. However, little evidence exists on the age-related skin and superficial fat tissue transformations in healthy individuals to guide targeted interventions.

METHODS

A quantitative sonographic assessment was conducted on 51 patients. Total soft tissue thickness (the skin and superficial fat compartments) was measured at eight sites along the jawline and four sites at the neck. Among them, 21 patients received botulinum toxin A (BTX-A) injections for jawline lift. Three-dimensional images and questionaries were obtained before and after the treatment.

RESULTS

In this ultrasound study, total superficial soft tissue thickness decreased significantly from the prejowl sulcus to the lateral cheek, with the jowl showing the greatest thickness. Vertically, significant differences in thickness were noted between superior and inferior points, especially at the inferior prejowl sulcus for the middle-aged and the jowl for the elderly group when comparing across age groups. Soft tissue thickness at the neck decreased from zones 1 to 3, consistent in all age groups. BMI and age positively correlated with soft tissue thickness at the jawline and neck. Regarding BTX-A injections, participants described a pain-free injection process, of which 85.7% reported substantial aesthetic improvement and sharpening of the submental-cervical angle.

CONCLUSIONS

This study quantified age-related changes in superficial soft tissues at the jawline and neck regions with ultrasound imaging. With aging, soft tissue thickness alters with high region-specificity. Tailoring interventions to the specific alterations within each age group can achieve optimal results with enhanced safety. This study provided a quantitative analysis of skin and superficial fat compartment thicknesses for the young, middle-aged, and elderly groups. This study illustrated how skin and superficial fat compartments change with age in a regionally specific manner for both the jawline and neck regions. This study revealed a positive association between BMI and age with skin and superficial fat tissue thicknesses, especially in areas like the jowl, submental, and neck. This study provided guidance for a safe and effective botulinum toxin. A injection method focusing on the injection depths and regions to achieve optimal jawline rejuvenation outcomes and patient experience.

LEVEL OF EVIDENCE IV

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Deciphering Depressor Anguli Oris for Lower Face Rejuvenation: A Prospective Ultrasound-based Investigation

BACKGROUND

The depressor anguli oris muscle (DAO) is a pivotal treatment target when creating a harmonic jawline. However, evidence of its live morphology remains scarce.

OBJECTIVES

In this study we aimed to reevaluate the DAO with a facile ultrasound analysis and thereby guide safer and more effective botulinum toxin type A (BTX-A) injection.

METHODS

A prospective ultrasound assessment was conducted in 41 patients. Morphology of the DAO and its relative position to neighboring structures were appraised at the ubiquitous facial landmark, the labiomandibular fold (LMF). Three-dimensional images were captured before and after the patient received the BTX-A injection based on sonographic evidence.

RESULTS

The skin-to-muscle depths of the DAO on average (measured from the medial to lateral border) were 5.26, 5.61, and 8.42 mm. The DAO becomes thinner and wider from zone 1 to zone 3 (P < .001). Overlapping lengths of the DAO and the depressor labii inferioris increased from zone 1 to zone 3: 4.74, 9.68, 14.54 mm (P < .001). The medial border of the DAO was located at 4.33, 6.12, 8.90 mm medial to the LMF (zone 1-3), and no muscle fibers of the DAO were observed in zone 1 or zone 2 in nearly one-third of patients. Improvement of the mouth corner downturn angle upon receiving BTX-A injection at zones 2 and 3 were 88.3%, 32.3%, and 14.7% for the neutral, maximum smile, and down-turning mouth corner expressions.

CONCLUSIONS

This work established an informative ultrasound portrait of the DAO and structures in the perioral region, which suggested the LMF as a convenient landmark for locating the DAO. Injection at the middle and lower thirds of the LMF at a 4- to 5-mm depth is recommended.