Dr. Ravi Thanage

Third Year MD Resident

27th June , 2014

Dept. of Medicine

Seth GSMC & KEMH

Scheme of the seminar

Anatomy

Etiologies

localisation on basis of clinical features

Pupillary abnormalities

Gaze palsies

Conclusion

Motor supply of extraocular and intraocular muscles.

Oculomotor nerve (Third CN)

Trochlear nerve (Fourth CN)

Abducent nerve (Sixth CN)

Oculomotor nerve

Nucleus lies in midbrain at the level of superior colliculus anterior to cerebral aqueduct.

Anatomy of oculomotor nucleus

Bilateral innervation

1) Edinger Westphalnucleus

2) Superior rectus

3) Levator palpebraesuperioris

Unilateral innervation

1) Medial rectus

2) Inferior rectus

3) Inferior oblique

Complete third nerve palsy Complete ptosis

Dilated pupil

Sluggishly reacting to light

Eye deviated lateral and downward

C/L eye partial ptosis with occasional associated superior rectus palsy

Nucleus:

Ipsilateral complete third nerve palsy

C/L ptosis and superior rectus palsy

Isolated levator subnucleus- isolated bilateral ptosis

Etiology: Infarction/Hemorrhage

Tumor

Multiple Sclerosis

Trauma

Infection

Fascicle Isolated fascicle-ipsilateral third nerve palsy

Weber’s syndrome: Fascicle + cerebral peduncleipsilateral third nerve and C/L hemiplegia

Nothnagel syndrome: Fascicle + cerebellar peduncle(dentatorubralfibres)ipsilateral third nerve and C/L ataxia

Benedikt syndrome: Fascicle + red nucleus/substantia nigraipsilateral third nerve and C/L choreiform movement

Claude’s syndrome:

fascicle + cerebellar peduncles + red nucleus

ipsilateral third nerve palsy, ipsilateral ataxia and contralateral tremors

Additional Etiologies: Osmotic demyelination

Ophthalmoplegic Migraine

(MRI may show enhancement of nerve at exit of midbrain)

Subarachnoid space

It is supero-medial to trochlear nerve and infero-lateral and parallel to PCA

It pierce the dura b/w free and attached margin of tentorium, to reach the cavernous sinus.

Ipsilateral complete third nerve palsy

Etiology :

1)Aneurysm of posterior cerebral, superior cerebellar or posterior communicating artery.

2)AV malformation.

3)Ophthalmoplegic migraine

4)Inflammatory Sarcoidosis, Wegener’s, Sjogren’s

5)Nerve infarction in DM, SLE and Temporal arteritis

Cavernous sinus

Palsy of all three nerves+

Painful – lateral lesions

(from temporal lobe abscess)

painless – Cavernous sinus thrombosis,

Tolosa Hunt syndrome

Mucormycosis

Arterial-venous fistula

Sphenoid sinus mucocele

Pitutary apoplexy, Adenoma

With Horner syndrome- likely forth nerve involvement

Orbit

Proptosis and isolated muscle involvement favours orbital pathology

Etiology: Granulomatous lesion

Pseudotumor cerebri

Inflammatory disorders

Metastases

Dural AVM

Trauma

Trochlear nerve 1. It is purely motor nerve, Supplies to Sup. Oblique

muscle.

2. The nerve is named for the trochlea, the fibrous pulley through which the tendon of the superior oblique muscle passes.

3. It is crossed, most slender, smallest nerve and has longest intra cranial course (7.5cm) of all cranial nerves.

4. It is only cranial nerve to emerge from dorsal aspect of brain

Nucleus Trochlear nucleus situated at

the level of sup. border of inferior colliculus.

It is in the dorsum of tegmentum of mid brain, ventrolateral to the cerebral aqueduct.

Dorsal to the medial longitudinal fasciculus.

At lower border of inf. Colliculus they turn medially to decussate in superior medullaryvelum.

Hence each Sup. Oblique is supplied from contralateral trochlearnucleus.

Affected eye is in upward gaze.

Unopposed inferior oblique action.

Abducent nerve Entirely motor nerve, supplies to lateral rectus muscle.

Most vulnerable cranial nerve, to be damaged in traumas and raised ICT, it crosses many bony prominences.

Nucleus Abducent nucleus is Small mass of large multipolar

cells, in floor of fourth ventricle, ventral to facial colliculus, where it is closely related to the horizontal gaze centre(PPRF).

fasciculus of the 7th nerve curves around the abducentnucleus.

Course and relation

Efferent fibres start from nucleus, traverse through tegmentum, Parapontineraticular formation(PPRF) and pyramidal tract .

Then leave the brainstem at pontomedullaryjunction, just lateral to pyramidal prominence.

Lateral to each abducentthere is the emergence of facial nerve.

Abducent nerve

Millard-gublersyndrome

ipsilateral sixth nerve

contralateral hemiplegia

Foville syndrome:

Extensive infarction involving sixth, seventh nerve nuclei and MLF and corticospinal tract

Sixth and V2 –nasopharyngeal carcinoma.

Gradenigo’s syndrome:

1. Acute apical petrositis

2. Ipsilateral sixth nerve palsy

3. Retro-bulbar pain ( trigeminal ganglion )

4. Deafness and ear discharge

Etiology: Middle ear infection, trauma, inferior petrosalsinus thrombosis.

Pupil Aperture of the diaphragm of eye (iris) that allows

light to enter the retina

FUNCTION

Controls amount of light entering the eye – influence of autonomic nervous system

Pupils are controlled by 2 muscles of ectodermalorigin –

1. Sphincter pupillae

2. Dilator pupillae

Normal size 3-5 mm

<3mm constricted

>5mm dilated

<1mm pin point pupils

Points to be kept in mind during examining pupils

Illumination of examination room should be low.

Patient should look into the distance.

Light used should be focused & bright.

Note the size, shape & contour of the pupil then test for reflexes.

Pupillary reflexes

Light reflexes

direct

indirect

Near reflex

Psychosensory reflex

Light reflex

DIRECT & INDIRECT

When light is shone in one eye, both the pupils constrict..

Constriction of pupil to which light is shone is directlight reflex and that of other is consensual ( indirect )light reflex.

If both optic nerves are intact, both pupils will be tightly constricted

(direct’ magnitude = consensual)

If one optic nerve damaged, both pupils dilate on showing the light to the diseased eye.

on swinging back to normal side, both pupils constrict

The dilatation or escape that occurs is called MARCUS GUNN PUPIL or RELATED AFFERENT PUPILLARY DEFECT (RAPD)

Near reflex

Convergence

Pupillary constriction

Accomodation

Accomodation Frontal eye field area

Nucleus of perlia (small set of neuron in medial rectus nuclei

Contraction of ciliary muscles

Increase in anterior curvature of lens

Psychosensory reflex

Refers to the dilatation of pupil in response to sensory and psychic stimuli.

Complex, mechanism still not elucidated.

e.g - Ciliospinal reflex

Anisocoria= unequal pupils

ANISOCORIA

Dilated pupil Constricted pupil

Well appreciated in bright light

Causes1)Pharmacological

2)Adie’s pupil

3)Third nerve palsy

4)RAPD

Well appreciated in dim light

Causes

1)Horner’s syndrome

2)Argyll Robertson pupil

3)Pharmacological

4) Pin point- opc, opiates, pontine

ANISOCORIA

HORNER’S SYNDROME

HORNER’S Syndrome

Miosis

Partial ptosis

Inverse ptosis

Enophthalmos (apparent)

Anhidrosis

Loss of ciliospinal reflex

Dilatation lag

Etiologies of Horner SyndromeCentral

Lat. Medullary syndrome

Anterior spinal artery thrombosis

Syphilis

Hypothalamic lesions

Sarcoidosis

Demyelination

Mutli system atrophy

Peripheral

Lung cancer

Cervical rib

Birth trauma(Klumpke’s)

Cavernous sinus

Diabetic autonomic neuropathy

High chest tube insertion.

Horner’s pupil

Congenital Horner Syndrome

Heterochromia irides

Low IOP

COCAINE TEST

Normal pupil dilates.

Horner pupil does not dilate.

Mechanism- prevents re-uptake of norepinephrine

1% HYDROXY AMPHETAMINE TEST

In PREGANGLIONIC lesions pupil will Dilates

Mechanism- releases the norepinephrine

Roots of ciliary ganglon:

1. Sensory root: comes from nasocilliary nerve

2. Parasympathetic root: arise from nerve to inf. Oblique muscle.

3. Sympathetic root: is a branch from int. carotid plexus.

Adie’s pupil

Large unilaterally dilated pupil

Absent or poor light response

Near slow tonic contraction

Absence of deep tendon reflex- Holme’s Adie’s syndrome.

Ciliary ganglion

Denervation super-sensitivity

Responds to very small doses of pilocarpine(0.125%)

Indicate postganglionic lesion

Adie’s pupil

Argyll Robertson Pupil Pupil slightly smaller in size

Near reflex present but Light reflex absent i.e there is light -near dissociation

Both pupils are involved, dilate poorly with mydraiatics

Hallmark of tertiary syphilis (neurosyphilis)

Etiology:

Encephalitis

Wernicke’s encephalopathy

Demyelination

Pineal tumour

Vasculitic disease.

Hutchison’s pupil

Lesions compressing nerve from outside causes dilatation of pupil before external ophthalmoplegia

e.g. Uncal herniation

Location of Pupillary fibres

Part of oculomotornerve which lies between brainstem and cavernous sinus, the pupillaryparasympathetic fibres are located superficially

Oculomotor nerve gets blood supply from various branches from basilar artery (in brain stem) and int & ext carotid artery

Pupillomotor fibres derive their blood supply from the pial blood vessels, whereas the main trunk is supplied by vasa nervosum

Medical third nerve palsy

DM, vasulitis affect vasanervosum, results in third nerve palsy with pupillary sparing.

Surgical third nerve palsy

Raised ICT , rupture of aneurysm affect pialblood vessels, results in pupillary involvement without ophthalmoplegia.

Hippus Alternate contraction dilatation of pupils

Creuzfeldt –Jacob Disease- Correspond to periodic sharp wave complexes (PSWC) on EEG associated with myoclonus

Aortic regugitation- Landolfi’s sign.

Ptosis and pupil

Ptosis wth dilated pupil - third nerve palsy

Ptosis with constricted pupil - Horner’s

Ptosis with normal sized pupil-

1)Neuromuscular causes: Myasthenia,

Snake bite

Botulism

2)Myotonia dystrophica

3) Infarction of nerve in vasculitis, DM

Gaze palsy

Gaze palsy

Conjugate Non-conjugate

Horizontal Vertical Horizontal Vertical

Horizontal conjugate gaze:

Toward lesion gaze preference-FEF, parietal lobe

Away from lesion- brainstem infarct

Vertical conjugate gaze:

dorsal midbrain syndrome

Non-conjugate horizontal gaze palsy:

Internuclear ophthalmoplegia

Non-conjugate vertical gaze palsy:

Progressive supranuclear palsy

Internuclear ophthamoplegiaMLF Syndrome -it is due to lesion of medial longitudinal fasciculus in pons -it connects 3rd ,4th & 6th nerve nuclei with vestibular nuclei

If left MLF having lesion –

- Vertical gaze unaffected

- Loss of left eye adduction

- Nystagmus in right eye on looking to right

- Convergence normal

- Also called as half syndrome

MLF Syndrome

One & Half Syndrome

single unilateral lesion of the paramedian pontine reticular formation and the ipsilateral medial longitudinal fasciculus

An alternative anatomical cause is a lesion of the abducent nucleus (VI) on one side(resulting in a failure of abduction of the ipsilateral eye and adduction of the contralateral eye = conjugate gaze palsy towards affected side), with lesion of the ipsilateral medial longitudinal fasciculus

Only movement present is contralateral eye abduction

Convergence unaffected

Vertical gaze unaffected