The "middle" section of the mouth muscles:
Zygomaticus major
Caninus (Levator anguli oris)
Origin above canine tooth
origin: canine fossa
insertion: orbicularis oris; skin at corner of mouth
action: pulls corner of mouth upward; together raises lower lip
insertion: orbicularis oris; skin at corner of mouth
action: pulls corner of mouth upward; together raises lower lip
Zygomaticus major
Origin on zygomatic bone
origin: zygomatic bone in front of suture
insertion: orbicularis oris; skin at corner of mouth
action: pulls corner of mouth upward and outward
insertion: orbicularis oris; skin at corner of mouth
action: pulls corner of mouth upward and outward
Buccinator
L. bucca—cheek
origin: alveolar processes of mandible
insertion: orbicularis oris; skin of the lips
action: pulls corner of mouth outward; compresses lips and cheeks
insertion: orbicularis oris; skin of the lips
action: pulls corner of mouth outward; compresses lips and cheeks
Orbicularis oris
L. orbicular—small disc + oris—of mouth
origin: fibers from the caninus, zygomaticus major and buccinator
insertion: lip-rim skin
action: closes and protrudes the mouth
insertion: lip-rim skin
action: closes and protrudes the mouth
Next: the muscles below the mouth.