3: Anatomy 2 - ear Flashcards Preview

ENT Week 1 2017/18 > 3: Anatomy 2 - ear > Flashcards

Flashcards in 3: Anatomy 2 - ear Deck (100)
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1
Q

Which bone protects the organs of hearing and balance?

A

Temporal bone

2
Q

What kind of nerve fibres innervate the ear?

A

Special sensory nerves

3
Q

Which cranial nerves are most responsible for hearing and balance?

A

CN VII (Facial nerve)

CN VIII (Vestibulocochlear nerve)

4
Q

What is the pterion?

A

Intersection of the

FRONTAL, PARIETAL, TEMPORAL and SPHENOID sutures

also the thinnest part of the skull

5
Q

What is the thinnest part of the skull and which bone is it found on?

A

Pterion

Temporal bone

6
Q

What is the lower part of the temporal bone called and why?

A

Petrous part

harder than the upper part

7
Q

What part of the temporal bone forms the outer opening of the ear?

A

External acoustic meatus

8
Q

What is the pointy projection at the lower part of the temporal bone which can be palpated behind the ear?

A

Mastoid process

9
Q

What is the thin projection from the temporal bone which acts as the insertion for some muscles of the tongue and pharynx?

A

Styloid process

10
Q

Which process attaches the temporal bone to the zygomatic bone?

A

Zygomatic process

11
Q

What are the three important processes of the temporal bone?

A

Mastoid process

Styloid process

Zygomatic process

12
Q

Which bone forms the hard palate?

A

Palatine bone

13
Q

Which bones make up the floor of the anterior cranial fossa?

A

Frontal, ethmoid and sphenoid bones

14
Q

Which bones make the floor of the middle cranial fossa?

A

Sphenoid and temporal bones

15
Q

Which bones make up the floor of the posterior cranial fossa?

A

Temporal and occipital bones

16
Q

Do the parietal bones make up the floors of any cranial fossa?

A

No (found on the walls)

17
Q

Where does CN I exit the cranial cavity?

A

Cribriform plate

18
Q

Where does CN II exit the cranial cavity?

A

Optic canal

19
Q

Where do CN III, IV, V1 and VI exit the cranial cavity?

A

Superior orbital fissure

20
Q

Where does CN V2 exit the cranial cavity?

A

Foramen rotundum

21
Q

Where does CN V3 exit the cranial cavity?

A

Foramen ovale

22
Q

Where do CN VII and VIII exit the cranial cavity?

A

Internal acoustic meatus

23
Q

Where do CN IX, X and XI exit the cranial cavity?

A

Jugular foramen

(so does the internal jugular vein)

24
Q

Where does CN XII exit the cranial cavity?

A

Hypoglossal canal

25
Q

What are the three general parts of the ear

A

External ear

Middle ear

Internal ear

26
Q

The external ear goes from the ___ to the ___ ___.

A

auricle

tympanic membrane

27
Q

What joins the auricle to the external tympanic membrane?

A

External acoustic meatus

28
Q

What is the purpose of the external ear?

A

Collects sound waves and conveys them to tympanic membrane

29
Q

The middle ear goes from the ___ ___ to the ___ ___.

A

tympanic membrane

oval window

30
Q

Apart from the tympanic membrane, ossicles and oval window, what other important structure is found in the middle ear?

A

Eustachian tube

31
Q

What is the purpose of the middle ear?

A

Amplifies sound

32
Q

The internal ear goes from the ___ ___ to the ___ ___ ___.

A

oval window

internal acoustic meatus

33
Q

What is the purpose of the internal ear?

A

Turns sound waves into action potentals

34
Q

What is the external ear called?

A

Auricle

35
Q

What is the posterior outer rim of the ear called?

A

Helix

36
Q

What is the rim of the ear next to the external acoustic meatus called?

A

Tragus

37
Q

Which nerves supplies sensory fibres for most of the posterior helix?

What is the exception?

A

C2 and C3

Tiny bit by CN VII

38
Q

Which cranial nerve supplies most of the inner helix and the external acoustic meatus?

A

CN V3 - mandibular division

39
Q

Which two cranial nerves supply the external acoustic meatus with sensory fibres?

A

CN V3

CN X

40
Q

Which lymph nodes drain the superior half of the auricle (facing forward)?

A

Parotid lymph nodes

41
Q

Which lymph nodes drain the superior half of the auricle (facing posteriorly)?

A

Mastoid lymph nodes

42
Q

Which lymph nodes drain the lower half of the auricle and the ear lobe?

A

Superficial cervical nodes

43
Q

Where does all lymph from the auricle eventually drain?

A

Deep cervical lymph nodes

44
Q

The external ear is made out of the temporal bone and elastic ___.

A

cartilage

45
Q

What is the technical name for the ear canal?

A

External acoustic meatus

46
Q

Which type of gland produces earwax in the external acoustic meatus?

A

Ceruminous glands

47
Q

What name is given to a medical device used to look inside the ear?

A

Otoscope / auriscope

48
Q

In a child, what shape is the external acoustic meatus?

A

Short and straight

49
Q

In an adult, what shape is the external acoustic meatus?

A

Curved

50
Q

What structure do you want to look at with an otoscope?

A

Tympanic membrane

51
Q

What are some important structures of the tympanic membrane?

A

Umbo (depressed part)

Pars flaccida (thin, superior part)

Pars tensa (thick, inferior part)

52
Q

Which cranial nerves supply sensory fibres to the

a) external
b) internal surfaces of the tympanic membrane?

A

a) CN V3 - mandibular division

b) CN IX - glossopharyngeal nerve

53
Q

What areas of the head and neck does CN IX supply?

A

Middle ear

Eustachian tube

Nasopharynx

Oropharynx

Tonsils

54
Q

CN __ supplies the middle ear, eustachian tube, nasopharynx and oropharynx with sensory nerve fibres.

A

CN IX

55
Q

What is the collective name for the three bones of the inner ear?

A

Auditory ossicles

56
Q

What are the three auditory ossicles called?

A

Malleus (mallet)

Incus (anvil)

Stapes (stirrup)

57
Q

Which auditory ossicle looks like an anvil?

A

Incus

58
Q

Which auditory ossicle looks like a mallet?

A

Malleus

59
Q

Which auditory ossicle looks like a stirrup?

A

Stapes

60
Q

Which type of joint connects malleus, incus and stapes?

A

Synovial joint

61
Q

What creates the umbo of the tympanic membrane?

A

Handle of the malleus pressing on it

62
Q

What space is found superior to the tympanic membrane?

A

Epitympanic recess

63
Q

What space is found posterior but not inferior to the tympanic membrane?

A

Tympanic cavity

64
Q

Which tube is found in the tympanic cavity and connects the middle ear to the nasopharynx?

A

Eustachian tube

65
Q

Which cranial nerve supplies the middle ear and the nasopharynx?

A

CN IX

66
Q

Why can pharyngitis or tonsilitis cause earache?

A

Referred pain as CN IX supplies both areas

67
Q

Apart from the eustachian tube, what other structure in the epitympanic recess is a tube which connects to the mastoid antrum?

A

Aditus

68
Q

Through which structure does the facial nerve travel to the stylomastoid foramen?

A

Internal acoustic meatus

Facial canal

69
Q

Where in the brainstem does the facial nerve arise?

A

Pons-medullary junction

70
Q

Which cranial bone is the internal acoustic meatus found in?

A

Temporal bone

71
Q

The facial nerve travels through the internal acoustic meatus and facial canal before emerging where?

A

Stylomastoid process

72
Q

Which tube connects the internal acoustic meatus to the stylomastoid process?

A

Facial canal

73
Q

What is a branch which comes off the facial nerve?

What does it supply?

A

Chorda tympani

Taste to anterior 2/3rds tongue

Parasympathetics to submandibular and sublingual glands

74
Q

The facial nerve innervates a muscle which stops the stapes from vibrating too much - what is it called?

A

Stapedius

75
Q

What are the functions of the facial nerve?

A

PARASYMPATHETIC - lacrimal, submandibular and sublingual glands

SOMATIC MOTOR - muscles of facial expression

SOMATIC SENSORY - tiny part of auricle

76
Q

Which other cranial nerve does the chorda tympani hitch a ride with to reach the submandibular and sublingual glands?

A

CN V3

Lingual nerve

77
Q

What are some of the muscles of facial expression?

A

Frontalis

Orbicularis oculi

Lip elevators

Orbicularis oris

78
Q

How can the motor function of CN VII be tested?

A

Ask patient:

frown

close eyes tightly

smile

puff out cheeks

79
Q

Which ganglion do lots of CN VII fibres synapse at in the facial canal?

A

Geniculate ganglion

80
Q

Which part of the ear is responsible for turning sound waves into action potentials?

A

Internal ear

81
Q

Which cranial nerve is responsible for hearing and balance?

A

CN VIII - Vestibulocochlear nerve

82
Q

Which parts of CN VIII are responsible for

a) hearing
b) balance?

A

a) Cochlear nerve

b) Vestibular nerve

83
Q

The vestibular nerve is responsible for ___.

The cochlear nerve is responsible for ___.

A

balance

hearing

84
Q

Through which structure do CN VIII fibres travel to the brain?

A

Internal acoustic meatus

85
Q

What is the complicated structure found in the internal ear which contains the cochlea and semicircular canals?

A

Otic capsule

86
Q

What are the spaces within the otic capsule called?

A

Labyrinths

87
Q

What are the two labyrinths found within the otic capsule?

A

Bony labyrinth

Membranous labyrinth

88
Q

The ___ labyrinth is found within the ___ labyrinth.

A

membranous WITHIN bony

89
Q

What kind of fluid is found within the

a) bony
b) membranous labyrinths?

A

a) Perilymph

b) Endolymph

90
Q

What fluid allows the membranous labyrinth to float within the bony labyrinth?

A

Perilymph

91
Q

Which structure of the otic capsule looks like a snail’s shell?

A

Cochlea

92
Q

What is the apex of the cochlea called?

A

Cupula

93
Q

Which nerve travels in the cochlea?

What is it responsible for?

A

Cochlear nerve

Hearing

94
Q

What are the long balloon-like structures which contain endolymph and the vestibular nerve?

A

Semicircular canals

95
Q

What is the path of soundwaves in the internal ear?

A

1. Sound wave vibrate tympanic membrane

2. Auditory ossicles vibrate

3. Stapes vibrates the oval window

4. Pressure waves in PERILYMPH activate HAIR CELLS

5. Hair cells release neurotransmitters and an action potential is conveyed to the brain by the cochlear nerve

6. Round window DAMPENS pressure waves

96
Q

What are the two windows found in the otic capsule?

What are they for?

A

Oval window and round window

Oval window is where the stapes vibrates and triggers a pressure wave

Round window is where the leftover pressure wave is dampened after an action potential has been generated

97
Q

Where do CN VII and CN VIII connect to the brainstem?

A

Pons-medullary junction

98
Q

The cochlear nerve and therefore hearing is controlled by the (cochlea / semicircular canals).

A

cochlea

99
Q

The vestibular nerve and therefore balance is controlled by the (cochlea / semicircular canals).

A

semicircular canals

100
Q

If you had an acoustic neuroma (tumour in the internal acoustic meatus) what symptoms would be produced on behalf of

a) CN VII
b) CN VIII?

A

a) Loss of function of muscles of facial expression, dry eyes (reduced lacrimation), dry mouth (reduced submandibular / sublingual secretions), loss of sensation at that little bit of the auricle, loss of taste

b) Loss of hearing, loss of balance