Anatomy - Clinical Anatomy of the Ear

Question 1

What is the thinnest part of the skull?

Answer 1

Pterion

Question 2

Why is a fracture at the pterion very dangerous?

Answer 2

The middle meningeal artery is located behind it

Trauma to this artery can cause an epidural haematoma

Question 3

The temporal bone is comprised of which two parts?

Answer 3

Squamous and petrous

Question 4

The zygomatic process is associated with which bone?

Answer 4

Temporal

Question 5

Which bones form the anterior cranial fossa?

Answer 5

1. Frontal
2. Ethmoid
3. Sphenoid

Question 6

Which bones form the middle cranial fossa?

Answer 6

1. Sphenoid
2. Temporal

Question 7

Which bones form the posterior cranial fossa?

Answer 7

1. Temporal
2. Occipital

Question 8

Which cranial nerve(s) enter the cranial cavity via the anterior cranial fossa?

Answer 8

Olfactory nerve

(via cribriform plate of the ethmoid bone)

Question 9

Which cranial nerves enter the cranial cavity in the middle cranial fossa?

Answer 9

1. CN II
2. CN III
3. CN IV
4. CN V (V1, V2 and V3)
5. CN VI

Question 10

CN VII enters the cranial cavity via which orifice?

Answer 10

Internal acoustic meatus

(in posterior cranial fossa)

Question 11

CN V2 enters the cranial cavity via which orifice?

Answer 11

Foramen rotundum

Question 12

Which cranial nerve(s) enter the cranial cavity via the superior orbital fissure?

Answer 12

1. CN III
2. CN IV
3. CN V1
4. CN VI

Question 13

CN V3 enters the cranial cavity via which orifice?

Answer 13

Foramen ovale

Question 14

Which cranial nerves enter the cranial cavity in the posterior cranial fossa?

Answer 14

1. CN VII
2. CN VIII
3. CN IX
4. CN X
5. CN XI
6. CN XII

Question 15

Which cranial nerve(s) enter the cranial cavity via the internal acoustic meatus?

Answer 15

1. CN VII
2. CN VIII

Question 16

Which cranial nerve(s) enter the cranial cavity via the jugular foramen?

Answer 16

1. CN IX
2. CN X
3. CN XI

Question 17

Which cranial nerve(s) enter the cranial cavity via the hypoglossal foramen?

Answer 17

CN XII

Question 18

By which term is the eardrum referred to?

Answer 18

Tympanic membrane

Question 19

Which areas can lymphatics from the ear drain firstly based on their location in the auricle?

Answer 19

1. Lateral surface of superior half - Parotid lymph nodes
2. Cranial surface of superior half - Mastoid lymph nodes and deep cervical
3. Rest of auricle and lobe - Superficial cervical lymph nodes

Question 20

All lymphatic drainage from the auricle will eventually follow which path?

Answer 20

1. Deep cervical lymph nodes
2. Thoracic duct or right lymphatic duct
3. Venous angle

Question 21

What is the name given to the thinnest aspect of the tympanic membrane?

Answer 21

Pars flaccida

Question 22

What is the name given to the thickest part of the tympanic membrane?

Answer 22

Pars tensa

Question 23

What is the name given to the most inwardly depressed area of the tympanic membrane?

Answer 23

Umbo

Question 24

What supplies general sensory supply to the external surface of the tympanic membrane?

Answer 24

CN V3

Question 25

What supplies general sensory supply to the internal surface of the tympanic membrane?

Answer 25

CN IX

Question 26

What are the bones which can be found in the middle ear?

Answer 26

1. Malleus 2. Incus 3. Stapes

Question 27

What creates the umbo?

Answer 27

Handle of malleus ataches at this point pulling in the tympanic membrane

Question 28

What is the name of the opening to the internal ear?

Answer 28

Oval window

Question 29

Why can tonsillitis or pharyngitis minic ear ache?

Answer 29

They have a shared sensory supply (CN IX) This is referred pain

Question 30

What connects the middle ear cavity to the nasopharynx?

Answer 30

Eustachian tube

Question 31

What is the function of the Eustachian tube?

Answer 31

Equalise pressure in the nasal and middle ear cavities

Question 32

Why may mastoiditis occur during a middle ear infection?

Answer 32

The mastoid process is a (posterior) boundary to the middle ear cavity Infection can easily spread

Question 33

How does CN VII connect to the CNS?

Answer 33

Brainstem at junction between pos and medulla

Question 34

What is the intracranial part of the course of CN VII?

Answer 34

Passes directly into internal acoustic meatus in posterior cranial fossa

Question 35

What is the temporal bone course of CN VII?

Answer 35

Through internal acoustic meatus Enters stylomastoid foramen

Question 36

How can CN VII act on the stapedius?

Answer 36

Reduces stapes movement to protect the inner ear from excessive noise

Question 37

Which branch comes off of CN VII in the middle ear cavity?

Answer 37

Chorda tympani

Question 38

What does the chorda tympani supply?

Answer 38

1. Taste buds of anterior 2/3rd of tongue 2. Parasympathetic supply to submandibular and sublingual glands

Question 39

When CN VII travels within the petrous aspect of the temporal bone, which canal does it lie within?

Answer 39

Facial

Question 40

The vestibulocochlear nerve is in which two parts?

Answer 40

1. Cochlear nerve - hearing 2. Vestibular nerve - balance

Question 41

The otic capsule will lie within which bone?

Answer 41

Temporal

Question 42

What does the otic capsule contain?

Answer 42

Bony labyrinth (fluid (perilymph) filled spaces inside the otic capsule)

Question 43

What 3 things are suspended within the perilymph of the bony labyrinth?

Answer 43

1. Membranous labyrinth 2. Communicating sacs and ducts 3. Endolymph fluid

Question 44

How many turns is there in the cochlea?

Answer 44

2.5

Question 45

What is the apex of the cochlear spiral called?

Answer 45

Cupula

Question 46

How many canals can be found in the otic capsule?

Answer 46

3 | (anterior, lateral, posterior)

Question 47

Action potentials from the semicircular ducts in the otic capsule will be conducted to the brainstem via which nerve?

Answer 47

Vestibular

Question 48

At which point do CN VII and CN VIII connect with the brainstem?

Answer 48

Junction between the pons and medulla oblongata

Question 49

Which structure can prevent dislocation at the TMJ?

Answer 49

Zycomatic process of the temporal bone

Question 50

Which canal transmits taste fibres to the anterior 2/3rd of the tongue

Answer 50

Facial canal

Question 51

What innervates the palatine tonsils?

Answer 51

CN IX

Question 52

What is the sensory innervation of the Eustachian tube?

Answer 52

CN IX

Question 53

Which 4 structures pass through the jugular foramen?

Answer 53

1. Jugular vein 2. CN IX 3. CN X 4. CN XI

Question 54

Where can the opening of the internal acoustic meatus be found?

Answer 54

Posterior cranial fossa

Question 55

A Le Fort type 1 fracture is most likely to damage what?

Answer 55

Nasolacrimal duct

Question 56

What is the smallest muscle in the body?

Answer 56

Stapedius