Nasalis Muscle, Lateral View

Description

Running across the midface, the nasalis muscle is shown in lateral view with its transverse part arising from the maxilla and sweeping superomedially over the nasal dorsum, while the alar part courses inferiorly toward the alar cartilage at the lateral margin of the nostril. Superiorly and slightly posterior to the ala, the fibers blend with the aponeurosis over the nasal bridge and interdigitate with adjacent perinasal mimetic muscles. The nasal skin and subcutaneous tissue sit superficial to these delicate slips, with the nasal cartilages deep to the alar portion. Lateral depiction matters because the nasalis is one of the primary dynamic determinants of nasal valve caliber, and its alar component can contribute to external nasal valve collapse when denervation, scarring, or prior rhinoplasty alters tension across the ala. Surgeons planning open or endonasal approaches benefit from a clear map of where muscle fibers lie relative to the alar cartilages and lateral crus, since aggressive dissection or cautery in this plane can produce postoperative alar retraction or asymmetry. Small muscle. Big functional consequences. Educators can drop this asset into head and neck anatomy modules on muscles of facial expression, emphasizing innervation by the buccal branches of the facial nerve and the muscle’s relationship to the nasal cartilaginous framework. It also suits ENT and plastic surgery teaching materials on nasal valve physiology, rhinoplasty surface anatomy, and botulinum toxin planning for perinasal “bunny lines,” where injection depth and placement aim to modulate nasalis activity without affecting the levator labii superioris alaeque nasi. Anatomical accuracy verified by SciePro's Medical Advisory Board.