Special Sense Organs Part 4

Question 1

T/F: The external acoustic meatus is about one inch in length and “S” shaped.

Answer 1

True

Question 2

What bone contains the medial 2/3 of the external acoustic meatus?

Answer 2

temporal bone

Question 3

T/F: the external acoustic meatus is covered by skin for its entire length and terminates at the chorda tympani.

Answer 3

False; terminates at the tympanic membrane

Question 4

What is cerumen and what produces it?

Answer 4

earwax produced by modified sweat glands (not sebaceous glands)

Question 5

How is otoscopic examination of the external acoustic canal made possible?

Answer 5

Because the canal is not straight, examination is possible by pulling out, down, and forward on the lobule (toward the chin)

Question 6

What arteries supply the external ear?

Answer 6

posterior auricular branch of the external carotid artery, anterior auricular branch of the superficial temporal artery, and auricular branch from the occipital artery

Question 7

What nerves supply sensory info to the external ear?

Answer 7

auriculotemporal nerve of the ophthalmic division of the trigeminal, auricular branch of the vagus, and great auricular nerve (C2 and C3)

Question 8

What branches supply motor info to the external ear?

Answer 8

temporal and posterior auricular branches of the facial nerve

Question 9

What ganglion provides sympathetics to the external ear?

Answer 9

superior cervical ganglion

Question 10

What is the small space between the tympanic membrane and the inner ear?

Answer 10

middle ear

Question 11

What two parts are recognized in the middle ear?

Answer 11

tympanic cavity and epitympanic recess

Question 12

What are the 3 small bones found in the middle ear?

Answer 12

incus, malleus, and stapes

Question 13

What 2 muscles are found in the tympanic cavity?

Answer 13

stapedius and tensor tympani

Question 14

What forms the roof or tegmental wall of the middle ear?

Answer 14

petrous part of the temporal bone

Question 15

A thin layer of bone separating the cavity of the middle ear from the internal jugular vein forms what boundary of the middle ear?

Answer 15

floor or jugular wall

Question 16

A small opening in the jugular wall allows the entrance of what nerve?

Answer 16

tympanic branch of the glossopharyngeal nerve

Question 17

T/F: the lateral or membranous wall of the middle ear is formed entirely by the tympanic membrane.

Answer 17

False; there is also a bony part of the lateral wall adjacent to the epitympanic recess.

Question 18

T/F: the posterior or mastoid wall of the middle ear is incomplete.

Answer 18

True

Question 19

What is the opening between the tympanic cavity and the mastoid air cells associated with the posterior (mastoid) wall?

Answer 19

the aditus of the mastoid antrum

Question 20

What is the opening that the tendon of the stapedius muscle passes through in the posterior wall of the middle ear?

Answer 20

pyramidal eminence

Question 21

T/F: there is an opening for the chorda tympani associated with the lateral wall of the middle ear?

Answer 21

False; posterior wall

Question 22

What wall separates the middle ear cavity from the internal carotid artery?

Answer 22

carotid wall

Question 23

What 3 openings exist in the carotid wall of the middle ear cavity?

Answer 23

a large opening for the pharyngotympanic tube, an opening for the tensor tympani to pass through, and a small opening for the chorda tympani to exit the cavity

Question 24

What is the boundary between the middle ear and the inner ear?

Answer 24

labyrinthine or medial wall

Question 25

What 5 landmarks are associated with the labyrinthine wall?

Answer 25

the promontory made by the cochlea, stapes attaches to the oval window, round window, prominence of the facial canal, and the lateral semicircular canal

Question 26

What landmark of the labyrinthine wall is covered by a plexus formed by the tympanic branch of CN IX and branches from the internal carotid plexus? What is this plexus called?

Answer 26

the promontory, an impression made by the cochlea; | tympanic plexus

Question 27

Mucous membranes of the middle ear, mastoid area, and pharyngotympanic tube are all supplied by what plexus?

Answer 27

tympanic plexus

Question 28

What nerve leaves the tympanic plexus and travels to the otic ganglion?

Answer 28

lesser petrosal nerve

Question 29

What landmark of the labyrinthine wall is an impression of bone formed by a canal conducting a major cranial nerve?

Answer 29

prominence of the facial canal (facial nerve)

Question 30

What 3 very small bones are located in the tympanic cavity?

Answer 30

malleus, incus, and stapes

Question 31

What is the largest of the middle ear bones which is in contact with the tympanic membrane?

Answer 31

malleus

Question 32

What bone transmits vibrations from the 1st and 3rd bones of the middle ear?

Answer 32

incus

Question 33

What bone of the middle ear is the 3rd bone? Its base sits against the oval window.

Answer 33

stapes