Nasalis Muscle

Description

Shown in lateral profile of the male head and upper neck, the nasalis muscle is highlighted over the nasal cartilages, with its transverse part (compressor naris) spanning superomedially across the dorsum of the nose and its alar part (dilator naris) coursing inferolaterally toward the ala nasi. Superiorly, fibers blend with the procerus near the glabella, while anterior and inferior fibers interdigitate with the levator labii superioris alaeque nasi along the lateral nasal wall. Medially, the muscle relates to the nasal septum and upper lateral cartilage; laterally it lies superficial to the maxilla and the nasal process. Small but specific. Functionally, this morphology matters because the transverse portion narrows the nasal aperture while the alar portion widens it, so their balance influences the external nasal valve during quiet breathing and forced inspiration. Rhinoplasty and alar base procedures frequently encounter these fibers, and preserving or selectively releasing them can change alar flare and resting nostril shape, a common postoperative complaint when scarring tethers the alar rim. The same anatomy explains why botulinum toxin placed too laterally can weaken dilation and worsen subjective obstruction, while targeted injection for idiopathic nasal flare aims at the dilator naris. Use this illustration when teaching facial expression musculature in gross anatomy, head and neck modules, or surgical anatomy for ENT and plastic surgery trainees, where clear relationships between the nasalis, neighboring perinasal elevators, and the alar cartilages support discussion of nasal valve mechanics and operative planning. It also suits figure plates for rhinoplasty technique chapters, facial nerve territory correlation, and patient education materials on functional nasal obstruction. Anatomical accuracy verified by SciePro's Medical Advisory Board.