Sonographic Analysis of the Upper Labial Orbicularis Oris and Its Clinical Implications

Abstract

Background Purse string lips, which include the vertical wrinkles over the lips, are frequently observed in aged individuals. Botulinum toxin and fillers are routinely injected into these areas to remove the wrinkles; however, the anatomy of the orbicularis oris muscle (OOr) near the vermilion border area has not been well defined. Objectives The aim of this study was therefore to identify any morphological differences of the upper OOr via sonographic imaging. Methods The upper lip muscles as observed utilizing an ultrasound device were divided into 2 muscles (pars peripheralis and pars marginalis) that were subsequently divided into a further 2 types (Type I and Type II) associated with the development of the pars marginalis. Type II was further divided into Type IIa and Type IIb depending on whether the muscle fibers were well developed and connected. Results On the midline of the lip, Type I, in which the pars marginalis was rarely observed and only appeared in traces, was observed in 20.0% of the volunteers. Type IIa, in which the pars marginalis was well-developed and appeared continuous, was observed in 42.9% of the volunteers. Type IIb, in which the pars marginalis was observed but appeared discontinuous, was observed in 37.1% of the volunteers. Conclusions The shapes of the upper pars marginalis of the OOr varied markedly between volunteers. Type classification of the OOr based on its shape and the lip appearance serves as a reliable source of reference information to be utilized when injecting botulinum toxin into the upper lip.

Anatomical Injection Guidelines for Glabellar Frown Lines Based on Ultrasonographic Evaluation

“…The use of US for minimally invasive procedures is increasing [17][18][19][20]. As already revealed in many facial US studies, the different echogenicity of the muscle and intramuscular tendon structures can be clearly demonstrated during dynamic movements [21].…”

Ultrasonographic analyses of Crow's feet and novel guideline for botulinum toxin injection

“…Several attempts have been made to utilize ultrasonography in guided injections in the musculoskeletal areas. 4,5 A previous study comparing conventional blind injection and ultrasonography-guided BoNT injection found that ultrasonography-guided injection successfully increased the safety and reliability during the procedure. When using ultrasonography, clinicians can precisely confirm the target muscle and needle position to avoid complications.…”

“…Furthermore, few studies have investigated the dynamic analyses of the formation of crow's feet, including detailed anatomical investigation of the orbital portion of the orbicularis oculi muscle via ultrasonography, to date. Several attempts have been made to utilize ultrasonography in guided injections in the musculoskeletal areas 4,5 . A previous study comparing conventional blind injection and ultrasonography‐guided BoNT injection found that ultrasonography‐guided injection successfully increased the safety and reliability during the procedure.…”