Posterior Dilator Naris Under The Skin, Lateral View

Description

Shown from a lateral head and neck perspective with the skin removed, the posterior dilator naris is isolated along the lateral wall of the external nose, blending with the alar region (ala nasi) and lying superficial to the lateral nasal cartilage. Nearby fibers of the nasalis (alar part) and levator labii superioris alaeque nasi frame the nasal aperture anteriorly, while the orbicularis oris and buccinator sit inferiorly around the upper lip and cheek. Posteriorly and inferiorly, the masseter overlies the mandibular ramus, and the sternocleidomastoid defines the anterolateral neck. Fiber direction is clear. For teaching nasal mechanics, this small slip matters because it is one of the few muscles that directly modulates the nostril margin and alar flare, counterbalancing compressive forces from the transverse part of nasalis and soft tissue recoil during inspiration. Clinically, alar collapse and dynamic nasal valve compromise often become obvious when dilator function is weak or denervated, as in facial nerve palsy, and reconstructive planning may consider alar batten grafting or suspension techniques that mimic dilator action. Lateral views also help you orient the muscle relative to the upper lateral cartilage and the soft-tissue triangle, landmarks that influence both rhinoplasty outcomes and airflow. Use this illustration in gross anatomy and head and neck anatomy courses when differentiating the muscles of facial expression around the nose from mastication muscles, and in ENT or plastic surgery teaching files discussing external nasal valve support, alar retraction, and postoperative functional assessment. It also fits well in atlas plates or patient-education materials explaining why nostril shape can change with facial nerve injury. Anatomical accuracy verified by SciePro's Medical Advisory Board.