The levator labii superioris alaeque nasi is one of the longest named muscles in the body, earning the informal title of the sneering muscle for its role in producing the sneer — simultaneously elevating the lip and flaring the nostril. Elvis Presley's famous lip curl was produced by hypercontraction of this muscle. It is a key target in the treatment of gummy smiles and nasal tip rotation in rhinoplasty planning.
| Origin | Frontal process of the maxilla adjacent to the nose |
|---|---|
| Insertion | Two slips: one to the alar cartilage of the nose and one to the upper lip skin |
| Nerve Supply | Buccal branch of the facial nerve (CN VII) |
| Blood Supply | Angular artery |
| Actions | Elevates the upper lip; Dilates the nostril (alar slip); Produces the sneering expression |
|---|
Its dual action of simultaneously elevating the lip and dilating the nostril links facial expression to airway opening, with its contraction during disgust and anger serving both emotional signalling and preparatory airway dilatation.
The angular artery, the terminal branch of the facial artery running along the LLSAN, is the vessel most commonly clipped in cosmetic filler injection complications causing skin necrosis in the nasolabial region. Knowledge of its course along the LLSAN is essential for safe perinasal filler injection.
Palpable along the lateral nose from the medial canthal region to the nasolabial fold junction, becoming firm during deliberate nostril flaring combined with upper lip elevation.
Accidental intravascular filler injection into the angular artery running alongside the LLSAN, causing skin necrosis of the nasolabial region requiring immediate hyaluronidase injection to dissolve filler and restore perfusion.
