QuestionSBA
QuestionChoice
Correct - Unreactive pupils means that the normal pupillary light reflex, involving cranial nerve II and cranial nerve III, has been impaired. Dilated pupils suggest that the sympathetic nervous innervation has not been affected, and the underlying pathology is likely to be a cranial nerve III lesion. This cranial nerve is situated in the midbrain.
10008370
a
Midbrain
QuestionChoice
Incorrect - This would not affect the pupillary light reflex. If the medulla were damaged the patient would have problems with breathing and swallowing. The gag, sneeze, and cough reflexes may also be lost.
10008372
c
Medulla
QuestionChoice
Incorrect - Damage to the frontal lobe may produce weakness on one side of the body or the face, impaired judgement, reduced sense of taste or smell, mood changes, or increased falls. The pupillary light reflexes would not be affected.
10008374
e
Frontal Lobe
QuestionChoice
Incorrect - The pons is responsible for unconscious processes such as the sleep-wake cycle and breathing regulation. Damage to the pons can cause the loss of all muscle function except for eye movement. Pupillary reflexes would still be intact.
10008371
b
Pons
QuestionChoice
Incorrect - The occipital lobe is not responsible for pupillary light reflexes. Damage to the occipital lobe would produce visual illusions, difficulties in colour processing, faulty distance and depth perception, and prosopangosia.
10008373
d
Occipital Lobe
Concept
Chapter
2693
4664
Pupillary Light Reflex
Topic
152
Neuroscience
14221
A 63-year-old man is brought into the Emergency Department after being found collapsed on the floor at home. He had two transient ischaemic attacks in close succession one month ago, as a result of vertebrobasilar insufficiency. On examination, his pupils are fixed and dilated.

Which of the following lesion sites would result in dilated pupils?
a