The Corneal Reflex | Pathway & Interpretation

The video tutorial explains the corneal reflex, involving cranial nerves 5 (trigeminal) and 7 (facial). It details the normal reflex process, where both eyes blink simultaneously when one is stimulated. The tutorial explores the effects of lesions on these nerves, showing how damage to the trigeminal nerve stops blinking in both eyes when the affected side is stimulated, while damage to the facial nerve prevents blinking in the lesioned eye regardless of which cornea is stimulated. The video emphasizes understanding the pathways over memorization.

Which cranial nerves are involved in the corneal reflex?

• Cranial nerves 5 and 7

• Cranial nerves 1 and 8

• Cranial nerves 3 and 6

• Cranial nerves 2 and 4

What is the primary function of the trigeminal nerve in the corneal reflex?

• Detecting sensation on the cornea

• Regulating tear production

• Motor function for eyelid closure

• Controlling pupil dilation

In a normal corneal reflex, what happens when one eye is stimulated?

• The opposite eye blinks

• Only the stimulated eye blinks

• Both eyes blink simultaneously

• Neither eye blinks

What happens if cranial nerve 5 on the left side is damaged?

• Only the right eye blinks when the left cornea is stimulated

• Only the left eye blinks when the left cornea is stimulated

• Neither eye blinks when the left cornea is stimulated

• Both eyes blink when the left cornea is stimulated

What is a consensual reflex in the context of the corneal reflex?

• A reflex that does not involve the brain

• A reflex where both eyes blink when one is stimulated

• A reflex where only one eye blinks

• A reflex involving only the facial nerve

How does a lesion on cranial nerve 7 affect the corneal reflex?

• Both eyes blink when either cornea is stimulated

• Only the affected eye blinks when its cornea is stimulated

• Neither eye blinks when the affected side's cornea is stimulated

• The unaffected eye does not blink when its cornea is stimulated

If the left facial nerve is damaged, what happens when the right cornea is stimulated?

• Only the left eye blinks

• Neither eye blinks

• Both eyes blink

• Only the right eye blinks

What is the best approach to understanding the corneal reflex for exams?

• Memorizing the pathways

• Drawing a rough sketch and understanding the pathways

• Ignoring the pathways and focusing on symptoms

• Learning only the definitions

What indicates a lesion in the facial nerve during a corneal reflex test?

• Both eyes blink regardless of stimulation

• No blinking in the affected eye regardless of stimulation

• The unaffected eye does not blink

• Only the affected eye blinks

What should you do if you have a question about the corneal reflex on an exam?

• Ignore the pathways

• Focus on the symptoms

• Understand the pathways and draw a sketch

• Memorize the results