Cranial nerves

Question 1

What is the normal width of the optic nerve (CN2)?

Answer 1

1.2 - 2.4mm

Question 2

What is the cavernous sinus and why is it important to look for?

Answer 2

It is the area right next to the sella turcica on either side where the internal carotids, CN3,4,5,6 live

This important because it a mass encompasses this area you can expect to see cavernous sinus syndrome or a lot of CN deficits

Question 3

How can you tell a quadrageminal cistern apart from a dermoid/epidermoid cyst in the 4th ventricle?

Answer 3

Dermoid/Epidermoid cysts continue to be hyperintense on T2 flair while quadrageminal cisterns null due to CSF involvement