Fourth nerve palsy is a condition caused by weakness or paralysis of the superior oblique muscle. This condition often causes vertical double vision as the weakened muscle prevents the eyes from moving in the same direction together.
Because the fourth cranial nerve is the thinnest and has the longest course of the cranial nerves, it is particularly vulnerable to traumatic injury.
To compensate for the double-vision resulting from the weakness of the superior oblique, patients characteristically tilt their head down and to the side opposite the affected muscle.
When present at birth, it is known as congenital fourth nerve palsy.
Famous quotes containing the words fourth, nerve and/or palsy:
“I asked my mother for fifty cents
To see the elephant jump the fence.
He jumped so high he reached the sky,
And didn’t get back till the Fourth of July.”
—Unknown. I Asked My Mother (l. 1–4)
“Tom: All right, boys. C’mon. Why don’t you say I’m a yellow belly and a big mouth at that?
Shep: You yellow? Who thinks you’re yellow? Did you hear what he said? A guy who’s got the nerve to marry? That’s more than Flash Gordon ever did.”
—Billy Wilder (b. 1906)
“The palsy plagues my pulses”
—Unknown. Tom o’ Bedlam’s Song (l. 37)