Which cranial nerves would NOT be affected by an internal carotid dissection?

• A. CN 1
• B. CN 3
• C. CN 4
• D. CN 6

Answer: (A)

Cranial nerve I, responsible for the sense of smell, is the correct answer because it does not pass through the skull in the same manner as the other cranial nerves listed. CN I travels from the olfactory bulbs located on the ventral surface of the frontal lobe directly through the cribriform plate of the ethmoid bone into the nasal cavity. In contrast, cranial nerves III, IV, and VI, which control eye movement, originate from the brainstem and traverse the cavernous sinus, making them vulnerable to complications from conditions like internal carotid dissection. Therefore, an internal carotid dissection primarily poses a risk to cranial nerves that traverse the area surrounding the internal carotid artery, whereas cranial nerve I remains unaffected due to its unique anatomical pathway.