Diplopia Impaired Ocular Movement

III nerve (contd)

On leaving the brain stem the nerve passes through the interpeduncular cistern close to the posterior communicating artery and runs towards the cavernous sinus.

Superior cerebellar artery

----Pupillary fibres lie superficially in the nerve.*

Posterior cerebral artery \

nerve

Posterior cerebral artery \

nerve

Superior cerebellar artery

nerve

Carotid arteries nerve

Carotid arteries

* This in part explains early pupillary involvement with III nerve compression and pupillary sparing with nerve infarction in hypertension and diabetes.

The nerve runs within the lateral wall of the cavernous sinus and then finally through the superior orbital fissure into the orbit. Here it divides into:

1. Superior branch to the levator of the eyelid and the superior rectus.

2. Inferior branch to the inferior oblique, medial and inferior recti.

Pituitary I

Pituitary I

VI nerve

Sphenoidal sinus

Internal carotid artery nerve ---IV nerve

VI nerve

Sphenoidal sinus

Internal carotid artery

Emerging IV nerves

Aqueduct

IV nucleus

--Medial lemniscus

TROCHLEAR (IV) nerve

This nerve supplies the superior oblique muscle of ilie eye.

The nucleus lies in the midbrain at the level of the inferior colliculus, near the ventral periaqueductal j-

grey matter. The nerve passes laterally and dorsally around the central grey matter and decussates in the dorsal aspect of the brain stem in close proximity to the anterior medullary velum of the cerebellum.

Emerging from the brain stem the nerve passes laterally around the cerebral peduncle and pierces the dura to lie in the lateral wall of the cavernous sinus. Finally, it passes through the superior orbital fissure into the orbit.

Midbrain

Emerging IV nerves

Aqueduct

IV nucleus

--Medial lemniscus

Corticobulbar and corticospinal tracts

Was this article helpful?

0 0
Supplements For Diabetics

Supplements For Diabetics

All you need is a proper diet of fresh fruits and vegetables and get plenty of exercise and you'll be fine. Ever heard those words from your doctor? If that's all heshe recommends then you're missing out an important ingredient for health that he's not telling you. Fact is that you can adhere to the strictest diet, watch everything you eat and get the exercise of amarathon runner and still come down with diabetic complications. Diet, exercise and standard drug treatments simply aren't enough to help keep your diabetes under control.

Get My Free Ebook


Post a comment