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)
Primary motor cortex (frontal lobe)
Oculomotor Nucleus
Superior colliculus (midbrain)
Superior colliculus (midbrain)
Pathway
Tegmentum, red nucleus, medial substantia nigra
Tegmentum, red nucleus, medial substantia nigra
Foramen
Superior orbital fissure
Superior orbital fissure
Division
Superior and inferior branches
Superior and inferior branches
Muscle
Superior branch - superior rectus, levator palpabrae superioris
Inferior branch - inferior rectus, medial rectus, inferior oblique
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)
Superior colliculus (midbrain)
Pathway
Tegmentum, red nucleus, medial substantia nigra
Tegmentum, red nucleus, medial substantia nigra
Foramen
Superior orbital fissure
Superior orbital fissure
Ciliary Ganglion
Muscle
Constrictor pupillae, ciliary muscles
Constrictor pupillae, ciliary muscles
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