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Home › Body Atlas › Muscles › Orbicularis Oris Labial Part
Muscle Head & Skull

Orbicularis Oris Labial Part

pars labialis m. orbicularis oris

The labial part constitutes the main body of the orbicularis oris, responsible for lip closure and compression. It receives contributions from the buccinator and other perioral muscles that decussate at the modiolus.

Anatomical Data

Origin, Insertion & Supply

OriginModiolus and perioral facial muscles, receiving fibres from buccinator, zygomaticus, and other perioral muscles
InsertionCentral dermis of the lip, blending with skin across the lip body
Nerve SupplyFacial nerve, buccal branches (VII)
Blood SupplySuperior and inferior labial arteries
Biomechanics

Function & Actions

Actions
  • Closes the lips
  • Protrudes the lips
  • Compresses the lips against the teeth

It purses and protrudes the lips, used for whistling, kissing, and sucking.

Clinical Relevance

Clinical Notes

The labial part is the component addressed in orbicularis oris reconstruction after cancer ablation. Perioral botulinum injection for smoker's lines targets the labial part superficially to reduce perioral vertical wrinkles. In total lip reconstruction, the orbicularis oris muscle must be re-created using adjacent muscle transfers.

Palpation

Palpated as the main lip body muscle during lip compression.

Pathology

Common Injuries & Conditions

Labial Orbicularis Resection in Lip Cancer

Segmental lip resection including the labial orbicularis producing a functional deficit requiring orbicularis reconstruction with cross-lip Abbe flap or other local flap to restore oral competence.

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