Clinical Anatomy of the Ear

Question 1

what bone houses the mechanisms for hearing and balance?

Answer 1

temporal

Question 2

what are the two parts of the external ear?

Answer 2

pinna

external acoustic meatus

Question 3

what marks the medial end of the external acoustic meatus?

Answer 3

the tympanic membrane

Question 4

what forms the pinna?

Answer 4

elastic cartilage attached to the temporal bone, encased in skin

Question 5

which part of the EAM is formed by cartilage?

Answer 5

the lateral third

Question 6

what is the EAM lined with?

Answer 6

skin continuous with the pinna, containing ceruminous glands

Question 7

what do ceruminous glands produce?

Answer 7

earwax

Question 8

what are the two parts of the temporal bone?

Answer 8

squamous

petrous

Question 9

what supplies the sensory nerve supply to the inferior part of the EAM and tympanic membrane?

Answer 9

CN X

Question 10

what supplies the sensory nerve supply to the superior parts of the EAM and most of the tympanic membrane?

Answer 10

CN V3 via the auriculotemporal nerve

Question 11

what supplies the sensory nerve supply to the superior portion of the helix?

Answer 11

C2 and C3 spinal nerves via the lesser occipital nerves

Question 12

what supplies the sensory nerve supply to the earlobe?

Answer 12

C2 and C3 spinal nerves via greater auricular nerve

Question 13

what is used to examine the EAM and tympanic membrane?

Answer 13

an otoscope

Question 14

what is the thin part of the tympanic membrane called?

Answer 14

pars flaccida

Question 15

what is the most inwardly depressed part of the tympanic membrane called?

Answer 15

the umbo

Question 16

what is the thick part of the tympanic membrane called?

Answer 16

pars tensa

Question 17

where is the cone of light normally directed in otoscopy?

Answer 17

anteroinferiorly

Question 18

what are the first bones to fully ossify during development?

Answer 18

the ossicles

Question 19

what is the function of the ossicles?

Answer 19

convey vibrations of the tympanic membrane due to sound and conduct them to the inner ear

Question 20

from lateral to medial, what are the ossicles?

Answer 20

malleus
incus
stapes

Question 21

what forms the connections between the ossicles and what does this allow?

Answer 21

small synovial joints

smooth movements between the bones

Question 22

how are the ossicles suspended in the tympanic cavity?

Answer 22

by small ligaments and mucosal folds

these carry small vessels and nerves that supply the ossicles

Question 23

what are the two muscles found in the tympanic cavity?

Answer 23

tensor tympani

stapedius

Question 24

where does tensor tympani insert?

Answer 24

malleus

Question 25

what innervates tensor tympani?

Answer 25

CN V3

Question 26

where does stapedius insert?

Answer 26

stapes

Question 27

what innervates stapedius?

Answer 27

CN VII

Question 28

where is the tympanic cavity located and what does it contain?

Answer 28

the petrous portion of the temporal bone contains the apparatus for the middle ear

Question 29

what are the two parts of the tympanic cavity?

Answer 29

tympanic cavity proper | epitympanic recess

Question 30

what nerve supplies the mucosa of the middle ear?

Answer 30

glossopharyngeal nerve | CN IX

Question 31

where is the epitympanic recess found?

Answer 31

superior to the tympanic membrane

Question 32

what is the opening in the posterior wall of the epitympanic recess called?

Answer 32

the mastoid aditus opens into the mastoid air cells

Question 33

what is the roof of the tympanic cavity called?

Answer 33

tegmen tympani

Question 34

what separates the tympanic cavity from the middle cranial fossa?

Answer 34

roof of the tympanic cavity

Question 35

what vessel is closely related to the floor of the tympanic cavity?

Answer 35

the internal jugular vein

Question 36

what are the four key features of the medial wall of the tympanic cavity?

Answer 36

oval window round window promontory facial canal

Question 37

what does the oval window do?

Answer 37

receives the footplate of the stapes

Question 38

what does the round window do?

Answer 38

dissipates forces from the cochlear

Question 39

what is the promontory?

Answer 39

the bump from the basal (first) turn of the cochlear

Question 40

what does the facial canal contain?

Answer 40

the facial nerve (CN VII)

Question 41

what is the connection between the middle ear and the nasopharynx called?

Answer 41

the eustachian tube

Question 42

where is the opening for the eustachian tube found in the nasopharynx?

Answer 42

posterior to the inferior nasal concha

Question 43

what forms the eustachian tube?

Answer 43

posterior third = bone rest = cartilage

Question 44

what is the role of the eustachian tube?

Answer 44

equalise air pressure between the middle ear and the nasopharynx

Question 45

what is the torus tubarius?

Answer 45

a feature of the nasopharynx caused by the cartilaginous opening of the eustachian tube

Question 46

what is the mucosa of the nasal cavity continuous with and how?

Answer 46

the mucosa of the middle ear via the eustachian tube

Question 47

where can pain from inflammation of the tonsils/pharynx be referred to?

Answer 47

the ear, causing otalgia

Question 48

where is the inner ear located?

Answer 48

deep within the petrous portion of the temporal bone

Question 49

what are the two main structures of the inner ear?

Answer 49

bony labyrinth | membranous labyrinth

Question 50

what is the bony labyrinth?

Answer 50

a fluid filled network in the otic capsule

Question 51

what is the membranous labyrinth?

Answer 51

a series of communicating ducts and sacs suspended in the bony labyrinth

Question 52

what parts of the inner ear are involved in hearing?

Answer 52

cochlear

Question 53

what parts of the inner ear are involved in balance?

Answer 53

semi-circular canals utricle saccule

Question 54

what are the three parts of the bony labyrinth?

Answer 54

cochlear vestibule semi-circular canals

Question 55

what is the cochlear?

Answer 55

a shell shaped spiral cavity encircling a bony core contains the round window

Question 56

what is the bony core of the cochlear called?

Answer 56

the modiolus

Question 57

what is the vestibule and what does it contain?

Answer 57

a small oval shaped chamber containing the utricle and saccule contains the oval window

Question 58

what are the vestibular organs?

Answer 58

utricle and saccule

Question 59

what are the semi-circular canals?

Answer 59

three bony canals that communicate with the vestibule are oriented at right angles to each other

Question 60

what suspends the membranous labyrinth in the bony labyrinth?

Answer 60

spiral ligament | delicate filaments

Question 61

which two semi-circular canals have a shared stalk?

Answer 61

posterior and anterior ducts

Question 62

what are the three semi-circular ducts?

Answer 62

anterior lateral posterior

Question 63

what achieves conversion of mechanical to neural stimuli in the inner ear?

Answer 63

specialised mechanoreceptors called hair cells

Question 64

where are the hair cells within the vestibular apparatus located?

Answer 64

maculae of the utricle and saccule ampullae of the semi-circular ducts

Question 65

how do the neural stimuli generated by hair cells reach the CNS?

Answer 65

via the vestibular nerve | a division of CN VIII

Question 66

where are the cell bodies for the neurons of the vestibular nerve located?

Answer 66

within the vestibular ganglion

Question 67

what are the three fluid filled channels that make up the cochlear?

Answer 67

scala vestibuli scala tympani cochlear duct/scala media

Question 68

what is the apex of the cochlear called and what ducts meet here?

Answer 68

helicotrema scala vestibuli and tympani

Question 69

where are hair cells located in the cochlear apparatus?

Answer 69

the organ of corti

Question 70

how do neural stimuli travel from hair cells of the cochlea to the CNS?

Answer 70

the cochlear nerve

Question 71

where are the cell bodies of the cochlear nerve located?

Answer 71

the spiral ganglion