Brain Stem
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Anterior View
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Posterior View
3
4
9,10,11
5
7&
Adducent
8th
12
Facial colliculus
Striae Medullare
Medulla Oblongata
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Nuclei in the medulla are
associated w/ autonomic
control, cranial nerves, and
motor/sensory relay.
Autonomic nuclei:
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Cardiovascular centers
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Respiratory rhythmicity
centers
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Cardioinhibitory/cardioacceler
atory centers alter the rate
and force of cardiac
contractions
Vasomotor center alters the
tone of vascular smooth
muscle
Receive input from the pons
Additional Centers
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Emesis, deglutition, coughing,
hiccupping, and sneezing
Medulla….
Medulla Sagittal Section And
Cranial Nuclei
Cranial Nuclei
Section of Medulla
Section of Medulla At the level
of Pyramid
Medullary syndromes
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Medial
Lateral medullary syndromes
Medial Medullary Syndrome
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Cranial Nerves
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Motor Pathways
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Tongue Paralysis Hypoglossal Nerve
Contralateral Spastic
Paralysis -- Pyramids
Sensory Pathways
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Contralateral loss Fine
Touch and
Proprioception -- Medial
Lemniscus
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Alternating
hemiplegia
Hypoglossal
Palsy
Lower Motor
Neuron
Syndrome
Deviation of Tongue to affected side
Atrophy of Tongue Muscles
Lateral medullary syndrome
(Wallenberg's syndrome)
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This is the commonest of the brain stem
strokes. Involvement of the spinothalamic
tract results in contralateral loss of pain
and temperature sensation below the
neck.
Involvement of the descending nucleus
and tract of V results in loss of pain and
temperature sensation on the face
ipsilateral to the lesion.
Lateral medullary syndrome
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Involvement of descending autonomic fibers
results in an ipsilateral Horner's syndrome
(ptosis, meiosis, and anhidrosis). Involvement of
the nucleus ambiguus causes palatal weakness
and dysphagia.
Involvement of the inferior cerebellar peduncle
(restiform body) causes ipsilateral ataxia.
Alternating hemianaesthesia
Brain stem Anterior view
Brain stem Posterior view
Section of Pons at the level of
Facial colliculus
Section of pons at the level of
trigeminal nuclei
Vestibular component of VIII
Nerve
Cochlear component of VIII
Nerve
Pontine syndromes
Medial pontine Syndrome
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Structures Associated
CST
Medial lemniscus
6th nerve fibers
7th nerve fibres
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Sign
Contralateral spastic
hemiparesis of the body
Contralateral loss of position
and vibration of the body
Medial strabismus
Raymond's Syndrome
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Alternating abducent
hemiplegia
Miller-gubler syndrome
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Alternating Facial hemiplegia.
Lateral pontine syndrome
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Structure
ICP
Spinal 5
Spinothalamic
Fibers of 7
Fibers of 8
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Sign
Ipsilateral limb ataxia
Ipsilateral pain and temp
loss - Face
Contralateral pain and
temp-Body
Horner’s syndrome
(Ipsilateral)
Hearing loss
Ipsilateral facial paralysis
Section of Mid Brain at Inferior
colliculus
Section of Mid Brain at superior
colliculus
At Superior colliculus
Ventromedial Superior Midbrain
Syndrome
(Weber’s Syndrome)
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Contralateral
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Ipsilateral
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paralysis of face, arm and leg
III palsy (fascicular)
Artery
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paramedian perforators of terminal basilar, or
peduncular perforating branches of posterior
cerebral artery
Paracentral (Tegmental) Superior
Midbrain Syndromes
(Claude’s and Benedikt’s
syndromes)
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Contralateral
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Ipsilateral
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ataxia with tremor (red nucleus) ±
hemichorea
(subthalamic nucleus)
III fascicular palsy
Artery
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paramedian perforators of terminal basilar,
or
interpeduncular branches of Posterior
Dorsal Superior Midbrain
Syndrome
(Parinaud’s, of Sylvian
Aqueduct)
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Paralysis of upgaze ± convergence
Light/near dissociation
Eyelid retraction
Convergence/retraction nystagmus
Artery - posterior choroidal/quadrigeminal
(Note - usually not vascular)
“Top of the Basilar” Syndrome
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Usually due to embolic occlusion
Posterior Cerebral Artery cortical territory
infarction (unilateral or bilateral)
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hemianopia/cortical blindness
amnesia
Basilar/Posterior Cerebral Artery
thalamic/midbrain territory infarction
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impairment of ocular movements (e.g. skew
deviation, vertical gaze palsies)
pupillary abnormalities (various)