Unit VIII - Ear Pt. 1

Question 1

What is the embryologic structure of ectodermal thickening on the lateral “head” that gives rise to the ears?

Answer 1

Placode

Question 2

What is the pathway of the embryological formation of the ear?

Answer 2

Placode –> auditory pit –> auditory vesicle –> most of membranous inner ear

Question 3

What structures of the ear are derived from the first pharyngeal pouch?

Answer 3

Auditory tube and tympanic cavity

Question 4

From where is the malleus derived?

Answer 4

Dorsal end of the ventral mandibular cartilage

Question 5

From where does the incus arise?

Answer 5

Dorsal end of the first pharyngeal arch

Question 6

What ear structure is derived from the dorsal end of the second pharyngeal arch?

Answer 6

Stapes

Question 7

From where does the tympanic membrane develop?

Answer 7

Interstitial mesoderm

Question 8

From where does the external acoustic canal develop?

Answer 8

First pharyngeal groove

Question 9

From where does the auricle develop?

Answer 9

A groove next to the first pharyngeal groove

Question 10

What are the three portions of the ear?

Answer 10

External, middle, and inner

Question 11

What is another name for the auricle?

Answer 11

Pinna

Question 12

What tissue makes up the auricle?

Answer 12

Cartilage

Question 13

What is the function of the auricle?

Answer 13

Funnel sound waves into the external acoustic meatus

Question 14

What are the three extrinsic ear muscles that position the auricle?

Answer 14

Anterior, superior, and posterior auricular muscles

Question 15

Which auricular muscle inserts on the front of the helix?

Answer 15

Anterior auricular muscle

Question 16

Which auricular muscle is the largest?

Answer 16

Superior auricular muscle

Question 17

Where does the superior auricular muscle insert?

Answer 17

On superior side of auricle

Question 18

What is the smallest auricular muscle?

Answer 18

Anterior auricular muscle

Question 19

Where does the posterior auricular muscle insert?

Answer 19

Lower, posterior aspect of concha

Question 20

What are the intrinsic ear muscles?

Answer 20

Helicis major and minor, tragicus, antitragicus, transverse muscles of the auricle, oblique muscles of the auricle

Question 21

About how long is the external acoustic meatus?

Answer 21

1 inch

Question 22

What shape is the external acoustic meatus?

Answer 22

S-shaped

Question 23

What part of the external acoustic meatus is within a bone? Which bone?

Answer 23

Medial 2/3; temporal bone

Question 24

What covers the entire length of the external acoustic meatus?

Answer 24

Skin with modified sweat glands

Question 25

What do the modified sweat glands of the external acoustic meatus produce?

Answer 25

Cerumen

Question 26

Where does the external acoustic meatus terminate?

Answer 26

Tympanic membrane

Question 27

What motion makes otoscopic examination possible even though the length of the external acoustic meatus is not straight?

Answer 27

Gently pulling out, down, and forward on the lobule

Question 28

What makes up the blood supply to the external ear?

Answer 28

Posterior auricular branch of external carotid artery Anterior auricular branch of superficial temporal artery Auricular branch from the occipital artery

Question 29

What makes up the sensory supply to the external ear?

Answer 29

Auriculotemporal nerve of the mandibular division of trigeminal Auricular branch of vagus Great auricular nerve (C2 and C3)

Question 30

What makes up the motor supply to the external ear?

Answer 30

Temporal and posterior auricular branches of the facial nerve

Question 31

Where does sympathetic supply to the external ear come from?

Answer 31

Superior cervical ganglion

Question 32

The middle ear is between what structures?

Answer 32

Tympanic membrane and inner ear

Question 33

What are the two parts of the middle ear?

Answer 33

Tympanic cavity and epitympanic recess

Question 34

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

Answer 34

Stapes, malleus, and incus

Question 35

What two muscles are located in the tympanic cavity?

Answer 35

Stapedius and tensor tympani

Question 36

What is the smallest muscle in the body?

Answer 36

Stapedius

Question 37

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

Answer 37

Petrous part of the temporal bone

Question 38

What forms the floor/jugular wall of the middle ear?

Answer 38

Thin layer of bone separating the cavity from the internal jugular vein

Question 39

The small opening in the floor/jugular wall of the middle ear serves what purpose?

Answer 39

Entrance for the tympanic branch of the glossopharyngeal nerve

Question 40

What forms the lateral/membranous wall of the middle ear?

Answer 40

Almost entirely by tympanic membrane (slight bony part adjacent to epitympanic recess)

Question 41

What wall of the middle ear is incomplete?

Answer 41

Posterior/mastoid wall

Question 42

What is the opening between the tympanic cavity and the mastoid air cells?

Answer 42

Aditus of the mastoid antrum (in the posterior/mastoid wall)

Question 43

What is the opening that the tendon of the stapedius muscle passes through and where is it located?

Answer 43

Pyramidal eminence; posterior/mastoid wall of middle ear

Question 44

Where do we find the opening for the chorda tympani?

Answer 44

Posterior/mastoid wall of middle ear

Question 45

The carotid wall of the middle ear separates the cavity from what vessel?

Answer 45

Internal carotid artery

Question 46

What are the openings found in the carotid wall of the middle ear?

Answer 46

Large opening for pharyngotympanic tube Opening for tensor tympani Small exit for chorda tympani

Question 47

Where does the chorda tympani enter and exit in the middle ear?

Answer 47

Enter - posterior/mastoid wall | Exit - carotid wall

Question 48

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

Answer 48

Labyrinthine/medial wall

Question 49

What is the impression made by the cochlea in the labyrinthine?

Answer 49

Promontory

Question 50

What covers the promontory of the labyrinthine, and what makes it up?

Answer 50

Tympanic plexus; tympanic branch of C.N. IX, branches from the internal carotid plexus

Question 51

What does the tympanic plexus that covers the promontory supply?

Answer 51

Mucous membranes of middle ear, mastoid area, and pharyngotympanic tube

Question 52

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

Answer 52

Lesser petrosal nerve

Question 53

What bone attaches to the oval window on the medial wall of the inner ear?

Answer 53

Stapes

Question 54

Where are the oval and round windows located?

Answer 54

Labyrinthine/medial wall

Question 55

The prominence of the facial canal is an impression of bone that is formed by a canal conducting what nerve?

Answer 55

Facial nerve

Question 56

In what wall does the lateral semicircular canal form a small impression?

Answer 56

Medial wall (labyrinthine)

Question 57

Where are the ossicles located specifically?

Answer 57

Tympanic cavity

Question 58

What is the largest auditory ossicle?

Answer 58

Malleus

Question 59

What does the malleus contact?

Answer 59

Tympanic membrane

Question 60

What is the function of the incus?

Answer 60

Transmit vibrations from malleus to stapes

Question 61

Where does the base of the stapes sit?

Answer 61

Against oval window

Question 62

What makes up the blood supply to the middle ear?

Answer 62

Anterior tympanic branch of internal maxillary artery | Tympanic branch of internal carotid artery

Question 63

What is the sensory nerve supply to the middle ear?

Answer 63

Tympanic nerve of C.N. IX

Question 64

What is the motor supply to the middle ear?

Answer 64

Nerve to the stapedius of the facial nerve | Medial pterygoid nerve of the mandibular division of the trigeminal

Question 65

What muscle does the medial pterygoid nerve of the mandibular division of the trigeminal nerve supply?

Answer 65

Tensor tympani

Question 66

What makes up the sympathetic supply of the middle ear?

Answer 66

Caroticotympanic nerves carry vasomotor and secretomotor fibers from superior cervical ganglion by way of internal carotid plexus