Muscle
Orbicularis oris
Shapes and seals the lips
High-yield
Its sphincter-like action closes the mouth, but its fibers do not form a simple uniform ring. Motor supply reaches it through branches of CN VII.
Overview
Orbicularis oris is an interwoven muscle complex within the upper and lower lips. It works with neighboring facial muscles to bring the lips together, project them forward and adjust their shape for speech and eating.
Reference facts
- Origin
- Muscle fibers around the mouth angles and fibers contributed by adjacent facial muscles, including attachments in the maxillary and mandibular regions
- Insertion
- Skin and mucosal tissues of the upper and lower lips
- Action
- Seals, compresses and protrudes the lips for coordinated oral movements
- Innervation
- Buccal and marginal mandibular branches of the facial nerve (CN VII)
- Blood supply
- Mainly the superior and inferior labial branches of the facial artery
Clinical correlation
Cleft lip can disrupt the alignment and continuity of this muscle complex. Restoring muscle position and function is an important part of reconstruction, alongside repair of the skin and other tissues.
Frequently asked questions
What does the orbicularis oris do?
The orbicularis oris seals, compresses and protrudes the lips for coordinated oral movements.
What nerve innervates the orbicularis oris?
The orbicularis oris is innervated by the buccal and marginal mandibular branches of the facial nerve (CN VII).
Where does the orbicularis oris attach?
Origin: Muscle fibers around the mouth angles and fibers contributed by adjacent facial muscles, including attachments in the maxillary and mandibular regions. Insertion: Skin and mucosal tissues of the upper and lower lips.
What is the blood supply of the orbicularis oris?
Mainly the superior and inferior labial branches of the facial artery.