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.
| Origin | Modiolus and perioral facial muscles — receiving fibres from buccinator, zygomaticus, and other perioral muscles |
|---|---|
| Insertion | Central dermis of the lip — blending with skin across the lip body |
| Nerve Supply | Facial nerve — buccal branches (VII) |
| Blood Supply | Superior and inferior labial arteries |
| Actions | Closes the lips; Protrudes the lips; Compresses the lips against the teeth |
|---|
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.
Palpated as the main lip body muscle during lip compression.
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.
