Novel anatomical proposal for botulinum neurotoxin injection targeting depressor anguli oris for treating drooping mouth corner

Abstract

The depressor anguli oris (DAO) muscle is a thin, superficial muscle located below the corner of the mouth. It is the target for botulinum neurotoxin (BoNT) injection therapy, aimed at treating drooping mouth corners. Hyperactivity of the DAO muscle can lead to a sad, tired, or angry appearance in some patients. However, it is difficult to inject BoNT into the DAO muscle because its medial border overlaps with the depressor labii inferioris and its lateral border is adjacent to the risorius, zygomaticus major, and platysma muscles. Moreover, a lack of knowledge of the anatomy of the DAO muscle and the properties of BoNT can lead to side effects, such as asymmetrical smiles. Anatomical-based injection sites were provided for the DAO muscle, and the proper injection technique was reviewed. We proposed optimal injection sites based on the external anatomical landmarks of the face. The aim of these guidelines is to standardize the procedure and maximize the effects of BoNT injections while minimizing adverse events, all by reducing the dose unit and injection points.

A practical guide to botulinum neurotoxin treatment of teres major muscle in shoulder spasticity: Intramuscular neural distribution of teres major muscle in cadaver model

“…16,26 The histologic observations of neuromuscular junctions show that the distance between the myelinated portion and the neuromuscular junctions is just a few microns. 26,27 This study provides evidence for an empiric approach to neurotoxin injection of the teres major based on anatomical data. Whether this technique improves efficacy or effectiveness will be determined only through clinical trials.…”

“…Because botulinum neurotoxin spreads a few centimeters from the injection site, the terminal myelinated portion can be used as a proxy marker for the neuromuscular junction 16,26 . The histologic observations of neuromuscular junctions show that the distance between the myelinated portion and the neuromuscular junctions is just a few microns 26,27 …”

The Effect of Polydioxanone Thread and Platelet Rich Plasma in Treating Myofascial Pelvic Pain

“…In the field of aesthetics and anti-aging procedures, botulinum neurotoxin injection and filler injections are most commonly practiced materials [9][10][11][12][13][14][15][16][17][18][19]. Recently, threads are used for the aesthetics surgery called thread facial lifting.…”

Retrospective Study of Horizontal Neckline Correction Using Absorbable Braided Polydioxanone Threads

“…Age-related transformations in the neck can involve various alterations, including the accumulation of submental fat, skin looseness causing the loss of the cervicomental angle, bone loss, and compromised neck contours resulting from jowl formation [16][17][18][19][20][21]. Various substances such as botulinum neurotoxin, dermal fillers, and skin boosters are employed in the realm of aesthetics to eliminate wrinkles [9,10,[22][23][24][25][26][27][28][29][30][31]. Aesthetic treatment of horizontal neck lines is one of the most common requests from patients looking to improve their neck's appearance.…”