Otolaryngologic Anatomy Flashcards

Which nerve crosses the middle ear between the malleus and the incus, medial to the tympanic membrane?

Answer: Chorda tympani

The chorda tympani runs through the middle ear between the handle of the malleus and the long process of the incus before leaving through the petrotympanic fissure.

Which nerve supplies the tensor tympani muscle?

Answer: Mandibular division of the trigeminal nerve

The tensor tympani comes from the first pharyngeal arch and is supplied by V3 through the nerve to the medial pterygoid.

The stapedius muscle is supplied by which cranial nerve?

Answer: Facial (CN VII)

The stapedius comes from the second pharyngeal arch and is supplied by a branch of the mastoid segment of the facial nerve.

Jacobson's nerve, which forms the tympanic plexus on the promontory, is a branch of which cranial nerve?

Answer: Glossopharyngeal nerve

Jacobson's nerve is the tympanic branch of CN IX; it carries the parasympathetic fibers that go on as the lesser petrosal nerve to the otic ganglion and parotid gland.

A patient coughs when the posterior external auditory canal is cleaned. Which nerve causes this reflex?

Answer: Auricular branch of the vagus nerve

Arnold's nerve (the auricular branch of CN X) supplies the posterior canal wall, and stimulating it can trigger a cough reflex.

What forms the lateral boundary of Prussak's space?

Answer: Pars flaccida of the tympanic membrane

Prussak's space is bounded laterally by the pars flaccida, medially by the malleus neck, superiorly by the lateral malleal fold, and inferiorly by the lateral process of the malleus.

Where is the most common site of facial nerve canal dehiscence?

Answer: Tympanic segment above the oval window

Bony dehiscence of the fallopian canal is most common in the tympanic segment, next to the oval window above the stapes.