Trochlear

Question 1

Which base of skull foramina does the trochlear nerve pass through?

Answer 1

Superior orbital fissure

Question 2

What type of information is carried on the trochlear nerve?

Answer 2

Motor

Question 3

What is the function of the trochlear nerve?

Answer 3

Motor supply to the superior oblique muscle

Question 4

Where are the cell bodies of the motor neurones of CNIV located?

Answer 4

Midbrain trochlear nuclei

Question 5

What are the functions of the superior oblique muscle?

Answer 5

Causes intorsion and depression of the eyeball

Question 6

The trochlear nerve is the only cranial nerve to do what 2 things?

Answer 6

Decussate, and to exit the cranial cavity posteriorly

Question 7

Once the trochlear nerve exits the midbrain (posteriorly), what does it do?

Answer 7

Wraps around the entire brainstem to find the anterior part again

Question 8

What is the consequence of CNIV exiting posteriorly and travelling around the brainstem?

Answer 8

It is a long, thin nerve which is easily disrupted

Question 9

Describe the intracranial course of the trochlear nerve?

Answer 9

Travels to the orbit along the lateral walls of the cavernous sinuses

Question 10

Describe the extracranial course of the trochlear nerve?

Answer 10

Supplies the superior oblique in the orbit

Question 11

How is the trochlear nerve tested?

Answer 11

H test to assess eye movements