Trochlear nerve

Presentation By:

Ayesha Aamir

Nazia Asghar

Trochlear Nerve

4th nerve

Each of the fourth pair of cranial nerves, supplying the superior oblique muscle (extraocular muscles) of the eyeball

origin

it is the only cranial nerve that arises from the back of the brain stem.

It is the smallest cranial nerve ,

It follows the longest course within the skull of any of the cranial nerves.

origin

Main nucleus

It has only one motor Nucleus ( trochlear nucleus)

Functions

Supplies the superior oblique muscles.

Turn the eyeball downwards and laterally.

Clinical symptoms

1. Trochlear Nerve Paralysis

It may not become symptomatic until later childhood or adulthood

Young children adopt a compensatory position head tilt in order to compensate for the underacting superior oblique muscle ( towards the contralateral sides)

Head is tilted as a compensatory adjustment, this may be the first indication of a trochlear lesion.

Patient cannot look downwards or inwards, has difficulty in descending stairs.

Clinical symptoms

2. Facial asymmetry due to chorionic head tilt

3. Vertical diplopia

IV Cranial nerve Palsy- Clinical Features

1- Lack of subjective features of torsion (Torsion: rotation of vertical corneal meridians)

2- Diplopia

Following Cataract surgery

Manifest transiently during pregnancy

3- Neck Pain after years of head tilting.

Treatment

Symptomatic cases can be treated with Strabismus Surgery.

Prism lenses set to make minor optical changes in the vertical alignment may be prescribed instead of or after surgery to fine-tune the correction.

Thank You