Week 1 - The Muscles of Facial Expression

Question 1

From what embryological structure are the muscles of facial expression derived?
Hence what is their nerve supply?

Answer 1

2nd pharyngeal arch

CN VII

Question 2

Name the 2 muscles of the orbital group

Answer 2

Orbicularis oculi

Corrugator supercilii

Question 3

State the 2 parts of orbicularis oculi and their actions

Answer 3

Outer orbital part - scrunches eyelid tight shut

Inner palpebral part - gently closes eyelid

Question 4

What 2 eye problems occur when the facial nerve is paralysed?

Answer 4

• Cornea dries out - exposure keratitis

- Lower eyelid droops - pooling of lacrimal fluid and no clearance of debris - ectropion

Question 5

What are the 2 major muscles in the oral group?

What are their actions?

Answer 5

Orbicularis oris - purses lips

Buccinator - pulls cheek in against teeth

Question 6

What are the 3 nasal muscles and what are their actions?

NB - one has 2 parts with opposing actions

Answer 6

• Nasalis - alar part flares nares, transverse part closes nares
• Procerus - pulls eyebrows down in frown
• Depressor septi nasi - flares nares

Question 7

Name the 3 groups of muscles of facial expression

Answer 7

Orbital
Nasal
Oral