self study - ear

Question 1

how can URTI cause otitis media?

Answer 1

back of throat + nasopharynx –> eustachian tube –> middle ear (otitis media)
ear pain main result from infection from back of throad and nasopharynx into middle ear via eustachian tube

Question 2

why do patients with a sore throat (URTI) sometimes complain of ear pain?

Answer 2

ear pain can be felt due to shared sensory innervation of the oropharynx with that of the inner surface of the tympanic membrane and middle ear cavity (CN IX - glossopharyngeal nerve)
oropharynx + internal surface of TM

Question 3

why might adenoids cause recurrent middle ear infections?

Answer 3

large adenoids obstruct nasal passage (choanae), can compress opening of eustachian tube - impedes ability to drain and ventilate middle ear
recurrent otitis media secondary to eustachian tube dysfunction (can’t drain or equalise air pressure) - or even glue ear
(remove adenoids to treat in children - disappeared by adulthood)

Question 4

sensory supply of auricle?

Answer 4

auriculotemporal nerve (V3) - area anterior to EAM
greater auricular nerve (C2/C3) - back of ear, helix/antihelix/lobule
small CN VII post-auricular

Question 5

sensory supply of external TM?

Answer 5

mainly auriculotemporal (V3)
some from auricular branch of vagus

Question 6

sensory to internal TM?

Answer 6

glossopharyngeal nerve (CN IX)