10. Fascicle Isolated fascicle-ipsilateral third
nerve palsy
Weber’s syndrome: Fascicle +
cerebral peduncle
ipsilateral third nerve and C/L
hemiplegia
Nothnagel syndrome: Fascicle +
cerebellar peduncle(dentatorubral
fibres)
ipsilateral third nerve and C/L
ataxia
Benedikt syndrome: Fascicle + red
nucleus/substantia nigra
ipsilateral third nerve and C/L
choreiform movement
11. 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)
12. 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.
13. 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
18. 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
19. Nucleus
Trochlear nucleus situated at
the level of sup. border of
inferior colliculus.
It is in the dorsum of
tegmentumof mid brain,
ventrolateral to the cerebral
aqueduct.
Dorsal to the medial
longitudinal fasciculus.
20. At lower border of inf.
Colliculus they turn
medially to decussate in
superior medullary
velum.
Hence each Sup. Oblique
is supplied from
contralateral trochlear
nucleus.
21. Affected eye is in upward
gaze.
Unopposed inferior
oblique action.
22. 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.
23. 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 abducent
nucleus.
24. Course and relation
Efferent fibres start from
nucleus, traverse through
tegmentum, Parapontine
raticular formation(PPRF)
and pyramidal tract .
Then leave the brainstem
at pontomedullary
junction, just lateral to
pyramidal prominence.
Lateral to each abducent
there is the emergence of
facial nerve.
29. 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
30. Pupils are controlled by 2 muscles of ectodermal
origin –
1. Sphincter pupillae
2. Dilator pupillae
Normal size 3-5 mm
<3mm constricted
>5mm dilated
<1mm pin point pupils
31.
32. 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.
35. DIRECT & INDIRECT
When light is shone in one eye, both the pupils
constrict..
Constriction of pupil to which light is shone is direct
light reflex and that of other is consensual ( indirect )
light reflex.
36. 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
37. The dilatation or escape that occurs is called MARCUS
GUNN PUPIL or RELATED AFFERENT PUPILLARY
DEFECT (RAPD)
38. Near reflex
Convergence
Pupillary constriction
Accomodation
39.
40.
41. 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
42. Psychosensory reflex
Refers to the dilatation of pupil in response to
sensory and psychic stimuli.
Complex, mechanism still not elucidated.
e.g - Ciliospinal reflex
51. 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
52. 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.
53.
54. 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.
55. Ciliary ganglion
Denervation super-sensitivity
Responds to very small
doses of pilocarpine
(0.125%)
Indicate postganglionic
lesion
57. 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)
60. Hutchison’s pupil
Lesions compressing
nerve from outside
causes dilatation of
pupil before external
ophthalmoplegia
e.g. Uncal herniation
61. Location of Pupillary fibres
Part of oculomotor
nerve which lies
between brainstem
and cavernous sinus,
the pupillary
parasympathetic fibres
are located
superficially
62. 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
63. Medical third nerve
palsy
DM, vasulitis affect vasa
nervosum, results in
third nerve palsy with
pupillary sparing.
Surgical third nerve
palsy
Raised ICT , rupture of
aneurysm affect pial
blood vessels, results in
pupillary involvement
without
ophthalmoplegia.
64. 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.
65. 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
69. Internuclear ophthamoplegia
MLF 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
71. 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
72. Only movement present is
contralateral eye abduction
Convergence unaffected
Vertical gaze unaffected
Notas del editor
PERIPHERAL PARASYMP GANGLION
At Apex of orbit- btwn Optic N & tendon of LR
