Ear anatomy

Question 1

blood supply to external ear

Answer 1

1. superficial temporal a.

2. posterior auricular a.

Question 2

external ear inn.

Answer 2

posterior: spinal nn. (lesser occipital, great auricular
anterior: cranial nn. (auriculotemporal (V3), CN VII, CN X)

Question 3

blood supply to tympanic membrane

Answer 3

1. anterior tympanic a.

2. deep auricular a.

Question 4

external surface of tympanic membrane inn.

Answer 4

GSA (ectoderm)

1. auriculotemporal n. (V3)
2. CN X

Question 5

internal surface of tympanic membrane inn.

Answer 5

GVA (endoderm)

tympanic n. (CN IX)

Question 6

embryonic origin of external accoustic meatus

Answer 6

1st pharyngeal cleft

Question 7

embryonic origin of tympanic membrane

Answer 7

1st pharyngeal cleft + 1st pharyngeal pouch + mesoderm

Question 8

embryonic origin of auricle

Answer 8

mesenchyme of 1st and 2nd arches

Question 9

only muscle that opens auditory tube

Answer 9

tensor veli palatini, CN V

Question 10

tensor tympani

Answer 10

dampens movement of ossicles, especially during chewing. CN V (2 “tens” or V)

Question 11

stapedius

Answer 11

dampens movement of ossicles, CN VII

Question 12

blood supply to middle ear

Answer 12

1. superior tympanic a.
2. inferior tympanic a.
3. anterior tympanic a.
4. posterior tympanic a.

Question 13

PS inn. to parotid gland

Answer 13

CN IX > tympanic n. > middle ear > lesser petrosal n. > otic ganglion > parotid

Question 14

3 branches of CN VII (internal and middle ear)

Answer 14

1. greater petrosal n (GVE-P)
2. n. to stapedius (SVE)
3. chorda tympani (GVVE-P, SVA)

Question 15

embryonic origin of middle ear and auditory tube

Answer 15

1st pharyngeal pouch

Question 16

embryonic origin of malleus, incus, and tensor tympani

Answer 16

1st pharyngeal arch

Question 17

embryonic origin of stapes and stapedius

Answer 17

2nd pharyngeal arch (ON TEST)

Question 18

embryonic origin membranous labyrinth and CN VIII ganglia

Answer 18

otic placode

Question 19

embryonic origin bony labyrinth

Answer 19

surrounding mesenchyme