The Anterior Morphological Structure of the Depressor Anguli Oris Muscle in a Male

Description

Originating along the oblique line of the mandible, the depressor anguli oris (triangularis) forms a superficial, triangular sheet in the lower face that runs superiorly and medially to the modiolus at the angle of the mouth. From an anterior perspective, its fibers frame the lateral aspect of the chin and sit lateral to the depressor labii inferioris, while the mentalis occupies a more midline, inferior position on the mental protuberance. Superiorly, the muscle blends with the orbicularis oris and interdigitates with neighboring elevators near the oral commissure, creating a layered architecture over the anterior mandibular body. Clear orientation, minimal ambiguity. Clinically, this muscle is a main driver of downward pull on the oral commissure and a common anatomic target in aesthetic and reconstructive work addressing marionette lines and lower-face asymmetry. Overactivity can accentuate a downturned mouth corner, while weakness or denervation, such as after marginal mandibular branch injury during submandibular gland surgery or facelift dissection, produces an asymmetric smile with impaired depression of the mouth angle. An anterior view helps distinguish depressor anguli oris from depressor labii inferioris, a frequent source of injection and surgical planning errors. Use this artwork in head and neck anatomy courses, facial expression modules, and oral and maxillofacial surgery teaching files that need a clean depiction of the lower perioral musculature in a male subject. It also suits atlases and clinical articles on botulinum toxin technique, facial nerve complications, and modiolus-centered perioral reconstruction. Anatomical accuracy verified by SciePro's Medical Advisory Board.