Overview
Roles
- Somatic motor - eye movement, eye opening
- Visceral motor (parasympathetic) - pupillary & ciliary muscles
Occulomotor Nerve Palsy
Abnormalities
- Eye deviated down and out
- Diplopia
- Ptosis
- Mydriasis (pupillary dilatation)
- Loss of pupillary reflexes
Causes of Oculomotor Nerve Palsy
- Small-vessel ischaemia
- Midbrain infarct
- Head trauma
- Tumour
- Aneurysm (commonly PCA)
Motor Pathway
- Eye movement and eye opening
- Cortical Centre
Primary motor cortex (frontal lobe)Oculomotor Nucleus
Superior colliculus (midbrain)Pathway
Tegmentum, red nucleus, medial substantia nigraForamen
Superior orbital fissureDivision
Superior and inferior branchesMuscle
Superior branch - superior rectus, levator palpabrae superioris
Inferior branch - inferior rectus, medial rectus, inferior oblique
Parasympathetic Pathway
- Pupillary and ciliary movement
- Edinger-Westphal nucleus
Superior colliculus (midbrain)Pathway
Tegmentum, red nucleus, medial substantia nigraForamen
Superior orbital fissureCiliary GanglionMuscle
Constrictor pupillae, ciliary muscles
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