Fourth nerve palsy

Fourth Cranial Nerve Palsy
Other names	Trochlear nerve palsy
Trochlear nerve
Specialty	Ophthalmology

Fourth cranial nerve palsy or trochlear nerve palsy, is a condition affecting cranial nerve 4 (IV), ^[1] the trochlear nerve, which is one of the cranial nerves. It causes weakness or paralysis of the superior oblique muscle that it innervates. This condition often causes vertical or near vertical double vision as the weakened muscle prevents the eyes from moving in the same direction together.^{[ citation needed ]}

Because the trochlear nerve is the thinnest and has the longest intracranial course of the cranial nerves, it is particularly vulnerable to traumatic injury.^{[ citation needed ]}

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.^{[ citation needed ]}

When present at birth, it is known as congenital fourth nerve palsy.^{[ citation needed ]}

See also

• Harada–Ito procedure

References

1. "Fourth Nerve Palsy". www.aao.org. Archived from the original on 30 January 2019. Retrieved 25 June 2019.