Posterior Dilator Naris, Gross Anatomy

Description

Arising from the lateral nasal wall, the posterior dilator naris is rendered deep to the transverse part of the nasalis, with its fibers tracking toward the ala of the nose and the margin of the naris. In lateral profile, its relationship to the nasal cartilages is clear, lying superficial to the nasal cavity lining but tucked beneath the more superficial nasal musculature that spans the dorsum and sidewall. The bony scaffold provides orientation, with the nasal bone and maxilla superior and posterior to the nostril, and the zygomatic arch and mandible placed farther posteriorly in the same sagittal plane. Cervical vertebrae and the hyoid sit inferiorly as positional landmarks rather than the primary subject. Small, deep, and easy to miss. Placement of the posterior dilator naris matters when you are teaching or documenting the muscular control of the external nasal valve, since dilation of the nostril depends on muscles that insert into and tension the alar tissues rather than acting on bone. Rhinoplasty and alar base procedures can weaken or scar the soft tissue supports at the ala, and awareness of the deeper dilator naris layer helps explain postoperative external valve collapse and persistent nasal obstruction even when septal alignment appears acceptable. This view also supports surface anatomy discussions, linking subtle facial expression movements and nasal flare to specific fiber directions and depth relationships. Use this image in head and neck gross anatomy courses, facial plastic surgery and ENT teaching files, and medical illustration plates discussing the nasalis complex and external nasal valve mechanics. It also fits well in publications on functional rhinoplasty, where differentiating the transverse nasalis from the deeper posterior dilator naris prevents oversimplified labeling. Anatomical accuracy verified by SciePro's Medical Advisory Board.