Muscles that insert into the Modiolus Flashcards
What are the functions of the orbicularis oris?
- Purses lips and presses them against lips
- Sphincter action of the lips
- Pulls the skin medially at dermal injection points
What is the orbicularis oris composed of?
- Long vertical segments that curl outward -> marginal protrusion
What facial branches innervate the orbicularis oris?
- Buccal
- Mandibular
In the upper lip, where does the orbicularis oris insert?
- Approx. 4-5 mm lateral from the midline (sparing the central region)
What is the function of the levator anguli oris?
Ellevates the commussure
Where does the levator anguli oris arise from?
Canine fossa of the maxilla beneath the infraorbital foramen
What facial nerves innervates the levator anguli oris?
- Buccal
- Zygomatic
What nerve and artery travel on the superficial surface of the levator anguli oris?
- Facial artery
- Infraorbital nerve
When contracted, what does the zygomaticus major do?
Elevates and laterally moves the commissure
Where does the zygomaticus major muscle arise from?
Zygomatic bone
(anterior to the zygomaticotemporal suture line and passes inferiorily and medially over the buccinator andlevator anguli oris)
Where does the zygomaticus major muscle insert?
Modiolus
The zygomaticus major inervates which branches of the facial nerve?
- Zygomatic
- Buccal
Describe the fibers of the zygomaticus major: supperiorly and inferiorily
Superiorily: deep to the orbicularis oculi muscle
Inferiorily: superficial to the facial vesselsandfacial nerve
Where are the 3 places that the buccinator arises from?
- Posterior alveolar process of the maxilla
- Ptergomandibular raphe
- Body of mandible
What is the function of the buccinator?
- Press lips and cheeks against teeth
What branch of the facial nerve does the buccinator innervate?
Buccal branches
What duct pierces the buccinator after it crosses the anterior edge of the masseter muscle?
Parotid
Where does the risorius arise from?
Parotid fascia
Where does the risorius insert?
Modiolus
What facial nerve branch does risorius innervate with?
Buccal branch
What happens when the risorius contracts?
Sardonic smile
Where does the depressor anguli oris arise from?
The oblique line on the anterior mandible below the canine and premolarteeth
Where does the depressor anguli oris insert?
Modiolus
What facial nerve is innervated by the depressor anguli oris?
Mandibular branch
(enters muscle on its deep surface)
What is the function of the depressor anguli oris?
Depress and laterally move the commissure
What is the platysma pars modiolaris?
Part of the platysma that is posterolateral to the depressor anguli oris, deep to the risorius
Where does the platysma pars modiolaris insert?
Muscles of lateral lowerlip
What does the platysma pars modiolaris do?
Depressor of the lower lip
