ear

Question 1

external acoustic meatus

Answer 1

• formed by cartilage and bone
• does not follow a straight course
• innervation V3 and vagus

therefore when examining the tympanic membrane important to pull the ear superior and lateral to try make the course as straight as possible when putting the otoscope in ear
(pull down in babies)

Question 2

lateral boundary of the middle ear

Answer 2

tympanic membrane

epitympanic recess

Question 3

floor of the middle ear

Answer 3

jugular wall

• internal jugular vein
• tympanic branch of glossopharyngeal nerve

Question 4

posterior wall of the middle ear

Answer 4

mastoid wall

• mastoid antrum
• mastoid air cells

Question 5

innervation of tympanic membrane

Answer 5

outer surface = V3

inner surface = 1X (9)

Question 6

medial wall of middle ear

Answer 6

labyrinthine wall

• promontory
• tympanic plexus
• oval and round window
• lesser petrosal nerve

Question 7

course of facial nerve leaving the skull

Answer 7

goes through the internal acoustic meatus runs through the facial canal and leaves via the stylomastoid foramen
- gives off chorda tympani nerve

Question 8

anterior wall of middle ear

Answer 8

carotid wall
- tensor tympanic muscle
- pharyngotympanic tube (eustachian tube)
- chord tympanic nerve
-

Question 9

contents of middle ear

Answer 9

auditory ossicles: malleus, incus, stapes
muscles: tensor tympani and stapedius
chorda tympani nerve: branch of facial
tympanic nerve plexus