CN III palsy and CN IV palsy

Question 1

What does CN IV (Trochlear) supply?

Answer 1

supplies superior oblique

Question 2

Function of the superior oblique muscle

Answer 2

depresses eye
moves inward

Question 3

Features of CN IV palsy

Answer 3

• vertical diplopia (noticed when reading a book or going downstairs)
• subjective tilting of objects (torsional diplopia)
• may develop a head tilt
• affected eye appears up and out