Dr. Mahziba RahmanMCPS, FCPS

Eye Specialist & Surgeon

Bangladesh Eye Hospital Ltd.

3rd cranial nerveOculomotor nerveEntirely motor in functionSupplies –• All the Extraocular muscles except superior oblique and lateral rectus• Levator palpebrae superioris• Intra ocular muscles- Sphincter pupillae and cilliary

muscle

NucleusLocated in midbrain at the level of superior

colliculus, ventral to the Sylvian aquiduct.

Composed of• Unpaired levator subnucleus• Paired superior rectus sub nuclei• Paired medial rectus, inferior rectus and

inferior oblique subnuclei• Unpaired Edinger-Westphal nucleus

Course

Can be divided into – Fascicular Basilar Intracavernous Intraorbital part

Course

Course

Intracavernous portion of 3rd nerve

Intraorbital portion of 3rd nerve

Major causes of nuclear complex lesion of 3rd nerve palsy

Vascular occlusion – Diabetes & Hypertension

Neoplastic lesions – primary tumour or metastasis

Haemorrhage

Major causes of fascicular lesion of 3rd nerve palsy

Vascular occlusion – Diabetes & Hypertension

Neoplastic lesions – primary tumour or metastasis

Haemorrhage

Demyelination

Syndromes of Fascicular lesion

Benedikt syndrome- Ipsilateral 3rd nerve palsy and contralateral extrapyramidal signs

Weber syndrome- Ipsilateral 3rd nerve palsy and contralateral hemiparesis

Nothnagel syndrome- Ipsilateral 3rd nerve palsy and cerebellar ataxia

Claude syndrome-

Major causes of lesion in Basilar region

The 3rd nerve traverses the basilar part unaccompanied by any other cranial nerves.

Isolated 3rd nerve palsies are commonly basilar.

The important causes areAneurysmHead trauma-Extradural or subdural

haematoma

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Major causes of Intracavernous lesion

Usually associated with involvement of 4th, 6th nerves & first division of 5th nerve.

Diabetes – causes pupil sparing 3rd nerve palsyPituitary apoplexyOthers – Aneurysm, Meningeoma, Carotid-

cavernous fistula.

Intraorbital causes of 3rd nerve palsy

Trauma

Vascular

Neoplasm

Inflammation

Pupillomotor fibersParasympathetic fibers

Located superficially between the brainstem and the cavernous sinus

Blood supply derived from the pial blood vessels

Main trunk of 3rd nerve supplied by the vasa nervorum

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Type of lesion affecting

Pupillomotor fibers :Surgical

Main trunk : Medical

Causes of isolated 3rd nerve palsy Idiopathic – about 25%

Vascular – Hypertension & Diabetes (commonly pupil sparing)

Aneurysm – posterior communicating artery at its junction with internal carotid artery

Trauma – subdural haematoma with uncal herniation

Miscellaneous

Clinical features of total 3rd nerve palsy

SYMPTOMS

Drooping of eyelid

Binocular double vision

Pain (may be present)

SIGNS

PtosisAbduction of globeIntortion of the globe which increases on

attempted down gazeLimitation of adductionLimitation of elevationLimitation of depressionDilated pupil with defective accommodation

History of PatientOnset

Duration

Diplopia

Trauma

Associated systemic disorders

ExaminationPupillary reactions

Motility restrictions

Ptosis

Other cranial nerves

Investigations

Age < 50 years CT or MRI, Cerebral angiography

Age > 50 years

Pupil sparing FBS and 2HABF, HbA1c, Lipid profile, Check BP, CBC with ESR, CRP

Pupil involving FBS and 2HABF, HbA1c, Lipid profile, Check BP, CBC with ESR, CRP, CT or MRI, Cerebral angiography

InvestigationsHess Chart

Treatment

Non-surgical

Treatment of underlying cause

Diplopia – Occlusion patch or prism in involved eye

Monitor children for development of amblyopia

Treatment

Surgical

Neurosurgery – Aneurysm or haematoma

Strabismus or ptosis surgery – Not earlier than 6 months from time of onset

Follow-up

Pupil sparing – Observe daily for 5 days for pupil involvement

Recheck every 4 to 6 weeks

If secondary to ischemia function usually returns within 3 months

Differential Diagnosis

Myasthenia gravis

Thyroid associated orbitopathy

Chronic progressive external ophthalmoplegia

Idiopathic orbital inflammatory disease

Thank you