External Ear

Question 1

how can the external ear be divided?

Answer 1

auricle/pinna
external acoustic meatus

Question 2

where does the external acoustic meatus end?

Answer 2

tympanic membrane

Question 3

what is the auricle and what is its function?

Answer 3

• paired struture that is found on either side of the head
• functions to capture and direct sound waves towards EAM

Question 4

what is the concha?

Answer 4

hollow depression in the middle of the auricle that continues into the skull as the external acoustic meatus

Question 5

what is the role of the concha?

Answer 5

directs sound into the EAM

Question 6

auricular haematoma

Answer 6

a collection of blood between the cartilage of the ear and the overlying perichondrium, usually as a result of trauma

Question 7

how can auricular haematoma result in cauliflower ear?

Answer 7

• accumulation of clood can disrupt blood suplly to the cartilage
• if untreated, avascular necrosis of cartilage can occur

Question 8

where does the external acoustic meatus extend?

Answer 8

from the deep part of the concha to the tympanic membrane

Question 10

the walls of the external 1/3 of the external acoustic meatus are formed from what? what about the inner 2/3?

Answer 10

external 1/3 - cartilage
inner 2/3 - temporal bone

Question 11

describe the path of the external acoustic meatus:

Answer 11

s-shaped curve:
* superoanterior direction
* turns and travels superoposteriorly
* ends by running inferoanterior

Question 12

what lies at the distal end of the external acoustic meatus?

Answer 12

tympanic membrane

Question 13

what is on the outside of the tympanic membrane? what is on the inside?

Answer 13

outside - skin
inside - mucous membrane

Question 14

how is the tympanic membrane connected to the surrounding temporal bone?

Answer 14

fibrocartilaginous ring

Question 15

how can the structures of the middle ear be observed during otoscopy, if the tympanic membrane sits in front of them?

Answer 15

tympanic membrane is translucent

Question 16

what occurs at the umbo of the tympanic membrane?

Answer 16

handle of the malleus attaches to the tympanic membrane

Question 17

what branches of the external carotid artery supply the external ear?

there are 4

Answer 17

• posterior auricular artery
• superficial temproal artery
• occipital artery
• maxillary artery - deep EAM and tympanic membrane only

Question 18

describe the sensory innervation of the external ear:

list 4

Answer 18

• greater auricular nerve - skin of auricle
• lesser occipital nerve - skin of auricle
• auriculotemporal nerve - skin of auricle and EAM
• branches of facial and vagus nerves - deeper aspects

Question 19

why do some people complain of an involuntary cough when cleaning their ears?

Answer 19

• auricular branch of vagus nerve is stimulated
• responsible for the cough refex

Question 20

what is the lymphatic drainage of the external ear?

Answer 20

superficial parotid, mastoid, upper deep cervical and superficial cervical nodes

Question 21

Label the auricle

Answer 21

Question 22

Label the tympanic membrane

Answer 22