Lecture 19 - The Face

Question 1

Growing a Face

Answer 1

1. Brachial arch formation: derived from gill structures in fish, dorsal cells migrate ventrally (patterning by Hox)
2. Placode development: specialized cells that give rise to the ear (otic), eye (optic), and nose (nasal)
3. Fusion: mandibular and maxillary processes fuse at the midline, shelves of the palate roate and fuse

Question 2

Function of the palate

Answer 2

-separates the nasal passage from the mouth during swallowing

Question 3

Palatal Muscles

Answer 3

• Tensor veli palatini muscle: CN V³
• Levator veli palatini muscle: CN X
• both elevate & stiffen the palate, attach at basicranium and soft palate

Question 4

What facial structure does the frontonasal prominence give rise to?

Answer 4

-upper face/forehead

Question 5

What facial structure do the nasal and maxillary prominences give rise to?

Answer 5

Midface

Question 6

What facial structures does the mandibular prominence give rise to?

Answer 6

Lower face

Question 7

What facial structure does the optic placode give rise to?

Answer 7

Eye

Question 8

What facial structure does the olfactory placode give rise to?

Answer 8

Nose

Question 9

What facial structure does the stomodeum give rise to?

Answer 9

Mouth

Question 10

What are the facial bones?

Answer 10

-zygomatic (2), maxilla, nasal (2), lacrimal (2), mandible, vomer, ethmoid, inferior nasal conchae (2), palatine (2)

Question 11

Facial Sinuses

Answer 11

-open spaces within the skull

Question 12

Anterior Eye Cavity Wall

Answer 12

-fibrous structure containing lids (tarsal plates) and septum

Question 13

Conjuctiva

Answer 13

-thin mucus membrane lining the eyelid and eye

Question 14

Eye Lubrication

Answer 14

Tears from lacrimal glands move inferior/medial across the eye, drain through punctum, canaliculi, to lacrimal sac and through nasal cavity

*runny nose when you cry: thinning mucus with tears

Question 15

Extrinsic Eye Muscles

Answer 15

-attachments: common tendinous ring, schlera

Question 16

Nasal Cavity

Answer 16

• turbinates create turbulence
• nasal septum: ethmoid, vomer, palatine and nasal cartilage
• nasal choana: common region posterior to nasal septum, anterior margin of nasopharynx

Question 17

Intrinsic Tongue Muscles

Answer 17

• 4 on the superior tongue
• innervated by CN XII

Question 18

Extrinsic Tongue Muscles

Answer 18

• styloglossus
• genioglossus
• hyoglossus
• palatoglossus
• all insert into intrinsic tongue muscles
• all innervated by CN XII or CN X

Question 19

Pharynx

Answer 19

-space at the back of the nose, mouth and throat

Question 20

Muscles of facial expression

Answer 20

Epicranius (frontalis + occipitalis), corrugator supercilii, orbicularis oculi, zygomaticus major, buccinator, orbicularis oris, platysma

• all attach to skull and facial skin
• innervated by CN VII

Question 21

What is the function of the epicranius muscle?

Answer 21

• Epicranius = frontalis + occipitalis
• brow elevation

Question 22

What is the function of the corrugator supercilii muscle?

Answer 22

-furrowed brow

Question 23

What is the function of the orbicularis oculi muscle?

Answer 23

-only muscle that closes the eyelid

Question 24

What is the function of the buccinator muscle?

Answer 24

• walls of cheek
• important during chewing

Question 25

What is the function of the orbicularis oris muscle?

Answer 25

-making kissy face

Question 26

What is the function of the platysma muscle?

Answer 26

-pulls inferiorly on the jaws and lower lip

Question 27

What is the function of the zygomaticus major muscle?

Answer 27

• smile
• dimples caused by a short zygomaticus major