Lecture 16 - Ear, Orbit, Oral, and Nasal Cavities

Question 1

What nerves innervate the outer ear?

RL16 S88

Answer 1

Sensory:

• great auricular
• auriculotemporal
• lesser occipital

Question 2

What nerves innervate the middle ear?

RL16 S90

Answer 2

Motor:

• stapedius (CN VII; facial)
• tensor tympani (CN V-3; trigeminal)

Sensory:
-CN IX; glossopharyngeal (tympanic and lateral petrosal)

Question 3

What nerves innervate the inner ear?

RL16 S92

Answer 3

CN VIII; vestibulocochlear:

• cochlea (auditory nerve)
• vestibule (vestibular nerve)

Question 4

What are the components of the vestibule?

RL16 S92

Answer 4

-utricle (with macula)
-saccule (with macula)
-semicircular canal
—distal ampulla

Question 5

What bones form the roof of the orbit and what are the special features?

RL16 S94

Answer 5

Components:

• frontal bone
• lesser wings of sphenoid bone

Features:
-fossa for lacrimal gland

Question 6

What bones form the floor of the orbit and what are the special features?

RL16 S94

Answer 6

Components:

• maxilla
• zygomatic bone
• palatine bone

Features:
-infraorbital groove and canal containing infraorbital nerve and infraorbital artery

Question 7

What bones form the medial wall of the orbit and what are the special features?

RL16 S95

Answer 7

Components:

• lacrimal bone
• frontal bone
• ethmoid bone

Features:

• fossa for lacrimal sac
• opening of nasolacrimal canal

Question 8

What bones form the lateral wall of the orbit and what are the special features?

RL16 S95

Answer 8

Components:

• zygomatic bone
• greater wing of sphenoid
• frontal

Question 9

What are the openings of the orbit and what do they contain?

RL16 S98

Answer 9

Superior orbital fissure:

• CN III
• CN IV
• CN V-1
• CN VI
• superior ophthalmic vein

Inferior orbital fissure:
-CN V-2

Optic canal:

• CN II
• ophthalmic artery

Question 10

What are the extrinsic muscles of the eye, their action, and innervation?

RL16 S99

Answer 10

Inferior oblique (CN III):
-abducts, elevates, laterally rotates

Superior rectus (CN III):
-elevates, medially rotates

Medial rectus (CN III):
-adducts

Inferior rectus (CN III):
-depresses, adducts, laterally rotates

Superior oblique (CN IV):
-abducts, depresses, medially rotates

Lateral rectus (CN VI):
-abducts

Question 11

What is the sensory innervation of the eye?

RL16 S100

Answer 11

Optic nerve

Ophthalmic nerve (CN V-1):

• lacrimal nerve
• nasocilliary nerve
• frontal nerve

Question 12

What is the innervation of the tongue and teeth?

RL16 S104

Answer 12

Tongue sensory:

• CN V-3 (anterior 2/3)
• CN IX (posterior 1/3)

Tongue taste:

• CN VII (anterior 2/3 taste)
• CN IX (posterior 1/3)

Tongue motor:
-CN XII

Teeth sensory:

• superior alveolar branch of CN V-2 (maxillary teeth)
• inferior alveolar branch of CN V-3 (mandibular teeth)