Cranial nerve origins, functions, and lesion presentations tested on USMLE Step 1.
31 cards · basic cards · AI-written, checked twice. Edit anything.
- What is the primary function of the olfactory nerve (CN I)?
Show answer
Smell (olfaction)- Through which skull opening does CN I pass?
Show answer
Cribriform plate of the ethmoid bone- What is the primary function of the optic nerve (CN II)?
Show answer
Vision- Through which skull opening does CN II pass?
Show answer
Optic canal- A lesion of CN II causes what visual deficit?
Show answer
Monocular blindness in the affected eye- Which extraocular muscles does CN III innervate?
Show answer
All extraocular muscles except the lateral rectus and superior oblique- Through which skull opening does CN III pass?
Show answer
Superior orbital fissure- Describe the classic resting eye position in a complete CN III palsy.
Show answer
The eye is deviated down and out- A CN III palsy with a dilated, nonreactive pupil suggests what type of cause?
Show answer
Compressive lesion, such as a posterior communicating artery aneurysm- A CN III palsy that spares the pupil suggests what type of cause?
Show answer
Ischemic or microvascular cause, such as diabetes- Which muscle does CN IV innervate?
Show answer
Superior oblique- A CN IV lesion causes difficulty with what eye movement?
Show answer
Looking down and inward, causing vertical diplopia- What is the general sensory function of CN V?
Show answer
Sensation of the face and anterior scalp- Besides sensation, what motor function does CN V provide?
Show answer
Muscles of mastication (chewing)- Through which opening does the ophthalmic division (V1) of CN V pass?
Show answer
Superior orbital fissure
FlashKeepers