Advertisements
What is the origin and course of Oculomotor nerve?
Oculomotor nerve is the 3rd cranial nerve. It Is purely motor nerve.
Origin: Its nuclei lie in midbrain at the level of superior colliculus.
Course
- It emerges from the ventral aspect of midbrain (in the interpeduncular fossa) between posterior cerebral and superior cerebellar arteries.
- Runs forward in the lateral wall of the cavernous sinus.
- Dives into two divisions– superior and inferior.
- Passes through the central part of superior orbital fissure to enter the orbit.
Name the nuclei, functional components and structures supplied by oculomotor nerve .
Following are the nuclei, functional components and the structures supplied by these:
Nuclei Functional component Structures innervated Oculomotor nucleus (in midbrain) GSE (General Somatic Efferent) Supplies following extraocular muscles:
Superior rectus, Inferior rectus, Medial rectus,
Inferior oblique and Levator palpabrae superiorisEdinger Westphal nucleus (in midbrain) GVE( General Visceral Efferent) Sphincter papillae and ciliaris muscles
Applied Aspects
Lesion of oculomotor nerve
The symptoms are:
- Lateral strabismus/squint: due to paralysis of medial rectus and unopposed action of lateral rectus muscle.
- Ptosis/drooping of upper eyelid: due to paralysis of levator palpebrae superioris.
- Dilated pupil: paralysis of sphincter papillae.
- Loss of accommodation: due to paralysis of medial rectus, sphincter papillae and ciliaris muscles.
- Diplopia on looking medially and superiorly.
It’s a very helpful link. Thank you so much. 😘