BRAINSTEM LESION INVOLVING 3rd,4th and 6th cranial nerve

1. Brainstem Lesions involving
3rd 4th & 6th Nerve and
Related Syndrome
GUIDE: CANDIDATE:
Dr. Ashish Patel Dr. Rajneesh Patidar

2. Oculomotor (Third cranial nerve)
• The oculomotor nerve is entirely motor nerve.
• Supplies Levator palpabrae superioris and all
extrinsic muscle of eye except lateral rectus and
superior oblique.
• Also innervates sphincter pupillae and cilliary muscle.

3. Course and relation
• Efferent fibres from 3rd
nerve nucleus.
• Pass through medial
longitudinal fasciculus,
red nucleus, substantia
nigra and medial aspect
of cerebral peduncle.
• Emerges from ventral
aspect of mid brain and
pass into
interpeduncular space.

4. Clinical Features of IIIrd Nerve Palsy
Symptoms :
1) Diplopia from misalignment of the visual axes
2) Symptomatic Glare in bright light (if the ptotic lid does not cover the
pupil)
Findings:
1) Involved eye usually is deviated down and out
(infraducted, abducted)
2) Ptosis (differentiated from myasthenia gravis by
TENSILLON TEST)
3) Pupillary Dilatation
4) Paralysis of Accommodation causes blurred
vision for near objects

5. Patient with third cranial nerve palsy

6. Localisation of Oculomotor Lesion

8. Lesion Affecting Third Nerve Nucleus
 Oculomotor Nucleus:
I/L complete 3rd nerve palsy + C/L Ptosis +
C/L Superior Rectus Paresis
 Oculomotor Subnucleus: Isolated Muscle Palsy
Isolated Levator Subnucleus: B/L Ptosis

9. Lesion Affecting Third Nerve Fasciculus
 Isolated Fascicle: Partial or Complete 3rd nerve
palsy with or without pupil involvement
 Paramedian Mesencephalon:
Plus Minus Syndrome (I/L Ptosis + C/L Lid
Retraction)
 Fascicle, Red Nucleus, Superior Cerebellar
Peduncle:
I/L 3rd nerve palsy + C/L Tremor and Ataxia
(CLAUDE Syndrome)

10.  Fascicle and Cerebral Peduncle: I/L 3rd nerve
palsy + C/L Hemiparesis
( WEBER Syndrome)
 Fascicle, Red Nucleus & Substantia Nigra:
I/L 3rd nerve Palsy + C/L Choreioform
Movement
(BENEDICT syndrome)

11. Lesions affecting 3rd nerve in Subarachnoid
Space:
Complete 3rd Nerve Palsy with or without
other cranial nerve involvement
 Lesions affecting 3rd nerve in Cavernous
Sinus:
 Painful or Painless CN 3rd Palsy with or without
Palsies of 4th, 6th and ophthalmic division of 5th
nerve
 Cranial Nerve 3rd palsy with small pupil (HORNER
SYNDROME)

12.  Lesions Affecting 3rd Nerve in Superior
Orbital Fissure:
Cranial Nerve 3rd Palsy with or without palsies
of Cranial Nerve 4th, 6th and Ophtalmic
Division of 5th with Proptosis.
 Lesions Affecting 3rd Nerve in the Orbit:
Oculomotor Nerve: Cranial Nerve 3rd Palsy
Optic Nerve: Visual Loss, Proptosis, Chemosis,
Swelling of Lids

13. Brainstem Lesions Involving
3th Nerve

14. Cross Section at the level of Upper
MidBrain

16. WEBER SYNDROME

17. Structure Damaged in Weber
Syndrome
• Corticospinal Tract: Contralateral hemiparesis and
typical upper motor neuron findings. It is
contralateral because it occurs before the
decussation in the medulla.
• Occulomotor Nerve Fibres: Ipsilateral
oculomotor nerve palsy with a drooping eyelid and
fixed wide pupil pointed down and out. This leads to
diplopia.

19. BENEDIKT’S SYNDROME
• Due to Vascular Ischaemia of tegmentum of
Midbrain.
• Area Involved
– Medial Lemniscus
– Spinal Lemniscus
– Trigeminal Lemniscus
– Red Nucleus
– Superior Cerebellar Peduncle
– Fibres of Oculomotor Nerve

20. Clinical Features
• Ipsilateral Lateral Squint and Ptosis(3rd Nerve)
• Contralateral loss of pain and temperature
sensation (Trigeminal & Spinal Leminiscus)
• Contralateral loss of tactile, muscle, joint &
vibration sense (Medial Leminiscus)
• Contralateral Tremors and involuntary
movements in limbs (Red Nucleus & Superior
Cerebellar Peduncle)

21. Trochlear Nerve Palsy

22. Trochlear Nerve
• Only Cranial nerve that comes out from dorsal
aspect of brain.
• Only Cranial nerve that crosses completely to
opposite side.
• Innervates Superior Oblique of contralateral
orbit.

23. Clinical Features
• Symptoms:-
– Diplopia: Acute onset of a vertical diplopia, which is more on
downward gaze, it is noted by patients while coming downstairs
and while doing near work.
• Signs:-
– Hypermetropia- The involved eye is higher as a result of
weakness of the superior oblique muscle, which becomes more
prominent when the head is tilted towards the ipsilateral
shoulder.
– Restricted ocular movements- There is limitation of depression
on adduction
– Abnormal head posture- To avoid diplopia, head takes a
posture towards the action of the superior oblique muscle, face
is slightly turned to the opposite side, chin is depressed, and
head is tilted towards the opposite side.

24. Characteristic Head Tilt

25. Localisation of Abducens Nerve
Lesions

26. Lesions Affecting Abducens Nucleus
 Abducens Nucleus: Gaze Palsy
Mobius Syndrome (Gaze palsy with Facial
Diplegia)
Duane’s Retraction syndrome (Gaze palsy with
globe retraction and narrowing of palpebral
fissure with adduction
 Dorsolateral Pons: Ipsilateral gaze palsy,
Facial paresis, Dysmetria, Ocassionally with
Contralateral Hemiparesis.

27. Lesions of the Abducens Fascicle
 Abducens Fascicle: Isolated CN 6th Palsy
 Anterior Paramedian Pons:
I/L CN 6th Palsy, I/L CN 7th palsy, C/L
Hemiparesis (Milard Gubler Syndrome)
 Prepontine Cistern:
CN 6th Palsy with or without C/L hemiparesis
(if Corticospinal tract involved)

28. Lesion of Abducens Nerve
 Petrous Apex (Dorello’s Canal) :
CN 6th palsy, Deafness, Facial pain specially retro-
orbital (Gradenigo Syndrome).
 Cavernous Sinus: Isolated CN 6th Palsy; CN 6th
Palsy plus Horner Syndrome, Also may affect CN 3rd ,
4th and 6th.
Superior Orbital Fissure Syndrome: CN 6th Palsy
with variable affection of CN 3rd, 4th, 6th, proptosis
 Orbit : CN 6th Palsy, Visual Loss, Variable Ptosis,
Chemosis, Lid Swelling.

29. Brainstem Lesions Involving
6th Nerve

33. INTERNUCLEAR
OPHTHALMOPLEGIA

34. • Internuclear ophthalmoplegia results from a
lesion in the MLF (Medial Longitudnal Fasciculus).
• In young people, the disorder is commonly
caused by multiple sclerosis and may be bilateral.
• In the elderly, internuclear ophthalmoplegia is
typically caused by stroke and is unilateral.
• Rarely, the cause is Arnold-Chiari malformation,
neurosyphilis, Lyme disease, tumor, head trauma,
nutritional disorders (eg, Wernicke
encephalopathy, pernicious anemia), or drug
intoxication (eg, with tricyclic antidepressants or
opioids).

35.  The MLF connects the following
structures:
• 6th cranial nerve nucleus (which controls
the lateral rectus, responsible for
abduction)
• Adjacent horizontal gaze center
(paramedian pontine reticular formation)
• Contralateral 3rd cranial nerve nucleus
(which controls the medial rectus,
responsible for adduction)

36. MECHANISM

37. • During horizontal gaze to the side
opposite the affected eye, images are
horizontally displaced, causing diplopia;
nystagmus often occurs in the abducting
eye.
• Sometimes vertical bilateral nystagmus
occurs during attempted upward gaze.

39. PSEUDO INO
• Due to involvement of Cranial nerves or
neuromuscular Junction
• MLF is not involved
• Seen in Myasthenia gravis, GBS
• Differentiating point from true INO-
Absence of adduction of affected eye
even after closure of C/L eye.

40. ONE AND A HALF
SYNDROME

41. One and a Half syndrome
 This uncommon syndrome occurs if a
lesion affects the horizontal gaze center(PPRF)
and the MLF on the same side.
The eyes cannot move horizontally to either
side, but the eye on the side opposite the
lesion can abduct with nystagmus while
abduction; convergence is unaffected.
 Causes include Demyelination (multiple
sclerosis), infarction, hemorrhage, and tumor.

42. One and a Half Syndrome

43. PARINAUD’S SYNDROME
• Parinaud syndrome, also known as the dorsal
midbrain syndrome, is a supranuclear vertical
gaze disturbance caused by compression of
the tectal plate.
EPIDEMIOLOGY
• Sporadic
• Causes: obstructive hydrocephalus,
mesencephalic hemorrhage, multiple
sclerosis, A/V malformation, trauma,
compression from tumor (pineal tumors)

44. It is characterised by:
• a deficiency in upward gaze
• Pupillary light-near dissociation (pupils
respond to near stimuli, but not light)
• convergence-retraction nystagmus
• Lid retraction (Collier’s sign)