Anterior Perspective of the Posterior Dilator Naris Muscle Under the Skin

Description

Frontal facial musculature is rendered with the posterior dilator naris (dilator naris posterior, part of the nasalis complex) isolated beneath the thin skin of the nasal ala. Small, obliquely oriented fibers lie lateral to the nasal cartilages and converge toward the alar margin, positioned inferior to the nasal bones and superior to the upper lip region. Medially, the highlighted slips approach the lateral nasal wall near the external naris, while laterally they blend into the superficial musculoaponeurotic layer over the cheek. Subtle anatomy. Big teaching value. Functionally, the posterior dilator naris contributes to flare and stabilization of the nostril during inspiration, counterbalancing compressive forces from adjacent nasal muscles and the elasticity of the alar cartilage. This anterior perspective helps clarify how small variations in fiber direction can change the external nasal valve area, a key concept in evaluation of nasal obstruction and in planning functional rhinoplasty or alar batten graft placement. It also supports teaching around facial nerve motor supply to the nasal region (buccal and zygomatic branches), where denervation, scarring, or post-traumatic distortion can reduce alar dilation and worsen inspiratory collapse. Use this asset in head and neck anatomy teaching modules, facial expression muscle plates for medical and dental textbooks, and ENT or plastic surgery publications discussing external nasal valve mechanics and alar contouring. It also fits well in clinical education materials on nasal airway assessment, where learners need a clear map of the nasalis and its relationship to the nostril rim. Anatomical accuracy verified by SciePro's Medical Advisory Board.