Brainstem and Cerebellum
Anatomy – Rostral to Caudal
Cranial Nerves:
3, 4, (5)
5, 6, 7, 8
(5), 9, 10, 11, 12
Anatomy – Medial to Lateral
Dorsal
Spinal cord
Brain stem
Ventral
Motor Nuclei - Medial
Sensory Nuclei - Lateral
Anatomy – Long Tracts
- Base
- Spinothalamic tract (Pain and temprature)
- Pyramidal tract (corticospinal) - motor
- Medial longitudinal fasciculus (MLF) – eye movements
Pyramidal tract runs in the base:
1. Ventral to cranial nuclei in the tegmentum (T) and to spinothalamic tract.
2. In the medulla also medial to the spinothalamic tract.
Long Tracts - Decussation
Corticospinal (pyramidal)
Lower Medulla
Posterior columns
Lower Medulla
Spinothalamic Spinal cord
- Lesions at medulla and below can result in dissociated sensory syndromes
- Lesions above the medulla will result in a contralateral upper motor neuron syndrome
Corticobulbar Tract
• Accompanies the corticospinal tract.
Decussation occurs at level of nucleus.
• Connects with the brain-stem motor nuclei.
• Each tract connects bilaterally with most cranial
nerve motor nuclei (except part of VII dealing
with lower face is innervated unilaterally and
Sometimes XII innervated unilaterally)
Posterior Circulation
Trigeminal Nerve (CN V)
Proprioception
Tactile
Pain and temperature
All fibers enter at Pons level but fibers conveying pain and temperature
Information descend to the spinal nucleus (down to C3)
Facial Nerve (CN VII)
Lesion proximal to the facial
nucleus will result in weakness
of the lower part of the face
(Central facial palsy)
Lesion at or distal to the facial
nucleus will result in weakness
of the upper as well as the lower
part of the face (peripheral facial
palsy)
Single Ocular Nerve Palsy
Oculomotor (III)
Trochlear (IV)
Abducens (VI)
Internuclear ophthalmoplegia (INO)
Disorder of conjugate lateral gaze in which the affected eye shows
impairment of adduction. The disorder is caused by injury or dysfunction
in the ipsilateral medial longitudinal fasciculus (MLF).
One-and-a-half syndrome
Lesion affecting the PPRF - paramedian pontine reticular formation (or the
abducens nucleus) and the MLF on the same side (the MLF having crossed
from the opposite side).
Lateral Medullary (Wallenberg) Syndrome
Causes – Vertebral artery or PICA (posterior inferior cerebellar artery) infarct
Vestibular nuclei –
Vertigo, nystagmus, nausea
Spinal tract of trigeminal nerve –
Ipsilateral facial pain and temperature
Sensation
Inferior cerebellar peduncle –
Ipsilateral cerebellar signs,
dysarthria
Sympathetic tract –
Ipsilateral Horner
Nucleus ambiguus –
Dysphonia, Dysphagia,
Vocal cord paresis
NOTICE
Pyramidal track is saved,
No significant limb paresis
Spinothalamic tract –
Contralateral pain and temperature
In limbs and trunk
Unknown origin –
Hiccups
Bulbar symptoms
Bulbar signs - dysarthria, dysphonia, dysphagia, salivation.
Bulbar Palsy
Pseudobulbar Palsy
Lower motor neuron
Upper motor neuron due to
bilateral damage
Signs of denervation
present - tongue atrophy
and fasciculation
Inappropriate spells of crying
and laughing, Jaw jerk and
gag reflex increased
Weight loss and risk of aspiration pneumonia present in both cases
Locked-in syndrome
With Infarcts caudal to the mid-Pons
consciousness is fully preserved but
the only movement possible are vertical
eye movements and blinking
Anatomy - Cerebellum
Vermis –
Gait and axial function
Each Cortical hemisphere
controls Contralateral Cerebellar
hemisphere
Each cerebellar cortex controls
ipsilateral side of body
Cerebellar hemispheres –
Limbs coordination
Flocculonodular lobe –
Eye movements and balance
Symptoms and signs of Cerebellar disease
(VANISH’D)
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•
•
•
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Vertigo.
Ataxia - usually falls towards lesion.
Nystagmus – usually increased with gaze towards lesion.
Intention Tremor.
Scanning speech, dysarthria.
Hypotonia.
Dysdiadochokinesia and Dysmetria.
Approach to differential diagnosis of
cerebellar dysfunction
Acute
Stroke
Focal
asymmetric - ischaemia
Chronic
Neoplastic
Demyelination
- haemorrhage
Demyelination
Diffuse
Symmetric
Drug intoxication:
• ethanol/ BZD/ Barbs
• anticonvulsants
Wernicke encephalopathy
Drugs: - alcohol
- phenytoin
Degenerative (hereditary)
Paraneoplastic
Creutzfeldt-Jacob disease
Hypothyroidism
Normal versus Pathological Nystagmus
Physiological
Never asymmetrical
Horizontal only
Pathological
Usually asymmetrical
Horizontal, vertical or
rotational
Fatigues
Usually persistent
Present only at extremes May be present at any
of horizontal gaze
position of gaze
Central versus Peripheral Vertigo
Peripheral (vestibular )
Central
Unidirectional
Uni or Bidirectional
Horizontal usually with
rotational component
Horizontal, vertical or
rotatory
Vertigo severe
Vertigo mild
May be associated with
tinnitus or hearing loss
Associated with other cranial
nerve, cerebellar or longtract signs
The end
Localization
Case 1
• A 64 year old right handed man with
sudden left side weakness that started 1.5
hours ago.
• Partial examination reveals left weakness
of lower face and left arm. His left leg is
only minimally effected.
• What is the most probable localization?
• Which other findings in examination are
expected?
• What is the differential?
• What ancillary radiology test will you
choose?
• What will be your treatment of choice?
Case 2
• A 68 year old right handed man with
sudden left side weakness that started 2
hours ago.
• Partial examination reveals left weakness
of lower face, left arm and left leg.
• What is the most probable localization?
• Which other findings in examination are
expected?
• What is the differential?
• What ancillary radiology test will you
choose?
• What will be your treatment of choice?
Case 3
• A 68 year old right handed man with
sudden difficulty understanding language
and disorganized speech.
• Partial examination reveals inability to
follow simple commands and fluent
speech, but un-comprehensible speech.
Naming is severely impaired.
• What is the most probable localization?
• Which other findings in examination are
expected?
• What is the differential?
• What ancillary radiology test will you
choose?
• What will be your treatment of choice?
Large vessel
Small Vessel
Presentation
Major vessels
Lacunar syndrome,
syndrome, hyperacute progressive over
hours
Etiology
Proximal Embolism
Atherosclerosis
Imaging in ER
CT angiography
CT without contrast
Immediate
Intervention
Intra-arterial
thrombolysis
Intravenous
thrombolysis
Case 4
• A 28 year old right handed woman with
impaired balance that started 5 years ago
and gradually progressed. Her older
brother and father had similar syndrome
that started in their 20’s.
• Examination revealed wide-based gait with
preserved reflexes.
Ataxia
• What is the localization?
• What is the most probable etiology?
Case 5
• A 24 year old right handed man complains
of drooling from his right corner of the
mouth and tearing. The symptoms started
5 days ago and gradually progressed.
• Examination of the cranial nerves is
normal except…..
• Additional finding in neurological
examination….
left leg
• What is the localization?
• How will you proceed?
Case 6
• A 27 year old right handed woman with
right eye blurred vision on the last 3 days.
No other neurological complaints.
• Examination revealed right RAPD,
nystagmus on right gaze, right up-going
toe and right ankle clonus.
• What is the localization?
• How will you proceed?
Thanks,