All Access Pass - 1 FREE Month!
Institutional email required, no credit card necessary.

4th Nerve Palsy

In CN 4 palsy, the superior oblique fails to activate. Thus, the affected eye is elevated (aka hypertropic).
CN 4 is long and thin and is the only cranial nerve to make a decussation; so its innervation originates from the opposite side of the brainstem.
Patients are often unaware of this deficit, because they produce a head tilt to counter it. They tilt their head to the side opposite the affected eye in order to bring their eyes into alignment.