Surgical consideration of the anatomic origin of the risorius in relation to facial planes

A Different Pattern of Arrangement of the Risorius Muscle Fibers: A Case Report

The risorius is a very thin muscle and is one of the superficial muscles of facial expression, which is reported as being inconstant, as it is absent in most people, and is a unique muscle; once it has no bony origin. The study aimed to report a different pattern of arrangement of the risorius muscle fibers. During a routine Anatomy class, a different pattern of arrangement of the risorius muscles fibers was found from the observation of an adult (around 40 years old) male cadaver hemiface (right side). After dissections, it was possible to note that the arrangement of the risorius muscle fibers on the surface of the masseteric fascia was formed in different arrangements formed in two bands. In conclusion, the risorius muscle fibers are not always easily distinguishable, and detailed knowledge of their different morphological arrangement is essential when planning and performing facial procedures.

Neuromodulating the SMAS for Natural Dynamic Results

Physicians using neuromodulators need to develop an in-depth and holistic understanding of the facial musculature as a single, large, functional structure that does not work in isolation. In this Special Topic, I review the anatomy of the continuous fibromuscular layer of the face, discuss how certain age-related indications develop as a consequence of imbalances to this unified structure, and propose considerations for neuromodulator-based interventions of the upper, mid, and lower face. I provide evidence-supported recommendations on the most optimal applications of neuromodulators to help rebalance the musculoaponeurotic layer for more natural outcomes. Through outcomes of my patients, I show how the facial mimetic muscles can be modulated with careful placement of botulinum toxin, without causing unnatural facial expressions, to achieve an expressive, well-balanced face that reflects health, vitality and happiness.

New method of recording the functional activity pattern of the buccinator from the mucosal surface

OBJECTIVES

The buccinator (BUC) is an important muscle for oral function. Since it lies deep in the facial skin, recording its activity is difficult; thus, studies on its function are limited. We developed a method to access the deep facial muscles from the mucosal side. The aim of this study was to test the reliability of the new recording method for the BUC and to investigate the BUC behavior in typical facial functions.

METHODS

To evaluate the new method, BUC activities were recorded simultaneously with a gel-type electrode on the skin and the newly developed surface electrode on the buccal mucosa. Electromyographic (EMG) activities in function, such as chewing and swallowing, along with the activities of the lower orbicularis oris (OO), zygomaticus major, masseter, and digastric muscles, were compared using the two recording methods. EMG activities among various tasks were compared using normalized values based on those obtained during maximum lip closure (MaxLC).

RESULTS

The new surface electrode was made of gold plates on a thin plastic fixed to a stainless-steel wire frame and weighed less than 1 g. The BUC activity recorded from the mucosa was the highest during a corner-pulling task and was low during clenching. The BUC was active during MaxLC, similar to the OO, and the BUC activity pattern among tasks recorded from the mucosa was identical to that reported by previous studies using intramuscular electrodes. The new electrode evaluated the BUC activities quantitatively, and the recordings by the new electrode were free from contamination.

CONCLUSIONS

The findings of this study confirmed the reliability of the new BUC recording method. It could be easily placed correctly within seconds, without the need for cleansing or sterilizing the skin. The BUC and OO were active during a MaxLC task, indicating that the BUC assists lip closure by pulling the corners of the mouth. The basic facial functions evaluated, including chewing, were similar to those studied by intramuscular electrodes.