levator labii superioris

musculus levator labii superioris

The levator labii superioris (or quadratus labii superioris) is a broad sheet, the origin of which extends from the side of the nose to the zygomatic bone. Its medial fibers form the angular head, which arises by a pointed extremity from the upper part of the frontal process of the maxilla and passing obliquely downward and lateralward divides into two slips. One of these is inserted into the greater alar cartilage and skin of the nose; the other is prolonged into the lateral part of the upper lip, blending with the infraorbital head and with the Orbicularis oris. The intermediate portion or infraorbital head arises from the lower margin of the orbit immediately above the infraorbital foramen, some of its fibers being attached to the maxilla, others to the zygomatic bone. Its fibers converge, to be inserted into the muscular substance of the upper lip between the angular head and the Caninus. The lateral fibers, forming the zygomatic head, arise from the malar surface of the zygomatic bone immediately behind the zygomaticomaxillary suture and pass downward and medialward to the upper lip. [WP,unvetted].

Type Bone
Latin Name musculus levator labii superioris
FMA ID 46805

Frequently Asked Questions

What is the levator labii superioris?
The levator labii superioris is a broad, flat facial muscle of expression that elevates the upper lip and contributes to creating the nasolabial fold. It lies in the superficial layer of facial muscles around the mouth.
What are the origin and insertion of the levator labii superioris?
The levator labii superioris originates from the frontal process of the maxilla and the infraorbital margin (from nose to zygomatic bone). It inserts into the skin and muscles of the upper lip, with some slips inserting into the greater alar cartilage.
What is the function of the levator labii superioris?
The levator labii superioris elevates (raises) the upper lip and dilates the nostril slightly due to its attachment to the alar cartilage. It also contributes to deepening the nasolabial fold, and is active during expressions of contempt or sadness.
What nerve innervates the levator labii superioris?
The levator labii superioris is innervated by the zygomatic and buccal branches of the facial nerve (cranial nerve VII), consistent with its classification as a muscle of facial expression.
What is the clinical relevance of levator labii superioris?
In facial nerve palsy (e.g., Bell's palsy), the levator labii superioris is paralyzed along with other facial muscles, causing drooping of the upper lip and loss of nasolabial fold depth on the affected side. It is also targeted in botulinum toxin treatment for a 'gummy smile.'

Related Structures

1st arch mandibular component ventral mandibular arch 1st arch mandibular ectoderm ectoderm of mandibular component 1st arch mandibular mesenchyme mandibular component mesenchyme 1st arch mandibular mesenchyme from head mesenchyme 1st arch mandibular mesenchyme from neural crest 1st arch maxillary component 1st arch maxillary ectoderm ectoderm of maxillary component 1st arch maxillary-mandibular cleft 1st arch maxillary-mandibular groove ectoderm

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Educational Disclaimer

This content is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider for medical decisions.

Data sources: Terminologia Anatomica, Foundational Model of Anatomy, Wikidata.