Lessons on Brainstem
LesionsDr. Dennis Bravo
CaseA 58 y/o was referred to you because of recent
onset of left hemiparesis, left-sided loss of propioception and right-sided tongue
deviation. What CNS structures are affected? Explain the symptoms with regards to
structures affected. Where is the lesion?
review of
Brainstem Structure
Brainstem Anatomy
MidbrainPons
Medulla
Brainstem Anatomy
MidbrainPons
Medulla
Rules of 4*
1. 4 structures in ‘midline’ and begin with ‘M’2. 4 motor nuclei in midline and are those that are divisors of 12 (3,4,6,12)3. 4 structures to the ‘side’ (lateral) and begin with ‘S’4. 4 CN in medulla, 4 in pons and 4 above pons
*Gates, P. The rule of 4 of the brainstem: a simplified method for understanding brainstem anatomy and brainstem vascular syndromes for the non-neurologist. Internal Medicine Journal 2005; 35: 263-266
4 Structures in midline and begin with ‘M’
4 Motor nuclei in midline and are divisors
of 12( 3, 4, 6, 12)
4 Structures to the side and begin with ‘S’
4 CN in medulla4 CN in pons
4 CN above pons
*Gates, P. The rule of 4 of the brainstem: a simplified method for understanding brainstem anatomy and brainstem vascular syndromes for the non-neurologist. Internal Medicine Journal 2005; 35: 263-266
231
4RULE of FOUR*
4 Structures in midline and begin with ‘M’
4 Motor nuclei in midline and are divisors
of 12( 3, 4, 6, 12)
4 Structures to the side and begin with ‘S’
4 CN in medulla4 CN in pons
4 CN above pons
*Gates, P. The rule of 4 of the brainstem: a simplified method for understanding brainstem anatomy and brainstem vascular syndromes for the non-neurologist. Internal Medicine Journal 2005; 35: 263-266
23 4
4 Structures in midline and begin with ‘M’
4 Motor nuclei in midline and are divisors
of 12( 3, 4, 6, 12)
4 Structures to the side and begin with ‘S’
4 CN in medulla4 CN in pons
4 CN above pons
*Gates, P. The rule of 4 of the brainstem: a simplified method for understanding brainstem anatomy and brainstem vascular syndromes for the non-neurologist. Internal Medicine Journal 2005; 35: 263-266
3 4
4 Structures in midline and begin with ‘M’
4 Motor nuclei in midline and are divisors
of 12( 3, 4, 6, 12)
4 Structures to the side and begin with ‘S’
4 CN in medulla4 CN in pons
4 CN above pons
*Gates, P. The rule of 4 of the brainstem: a simplified method for understanding brainstem anatomy and brainstem vascular syndromes for the non-neurologist. Internal Medicine Journal 2005; 35: 263-266
4
4 Structures in midline and begin with ‘M’
4 Motor nuclei in midline and are divisors
of 12( 3, 4, 6, 12)
4 Structures to the side and begin with ‘S’
4 CN in medulla4 CN in pons
4 CN above pons
*Gates, P. The rule of 4 of the brainstem: a simplified method for understanding brainstem anatomy and brainstem vascular syndromes for the non-neurologist. Internal Medicine Journal 2005; 35: 263-266
4 Medial Structures
•Motor pathway•Medial leminiscus•Medial longitudinal fasciculus•Motor nucleus and nerve
RULE #1
4 Medial Motor Nucleus
•CN divides number 12•CN 3, 4, 6, 12 are midline•3, 4, 6, 12 nucleus are midline•5, 7, 9, 11 lateral
RULE #2
4 Side Structures
•Spinocerebellar pathway•Spinothalamic pathway•Sensory nucleus of CN5•Sympathetic pathway
RULE #3
4 Medulla Cranial Nerves
•Glossopharyngeal (CN9)•Vagus (CN10)•Spinal accessory (CN11)•Hypoglossal (CN12)
RULE #4
4 Pons Cranial Nerves
•Trigeminal (CN5)•Abducent (CN6)•Facial (CN7)•Auditory (CN8)
RULE #4
4 Cranial Nerves Above Pons
•Olfactory (CN1)•Optic (CN2)•Occulomotor (CN3)•Trochlear (CN4)
RULE #4
Motor pathway(Corticospinal tract)
Medial lemniscus
Medial longditudinal fasciculus
Motor nucleus and nerve
Contalateral weakness
DEFICITMidline
Structu
res
More Info
Motor pathway(Corticospinal tract)
Medial lemniscus
Medial longditudinal fasciculus
Motor nucleus and nerve
Contalateral weakness
Contralateral propioception/ vibration loss
DEFICITMidline
Structu
res
More Info
Motor pathway(Corticospinal tract)
Medial lemniscus
Medial longditudinal fasciculus
Motor nucleus and nerve
Contalateral weakness
Contralateral propioception/ vibration
loss
Ipsilateral internuclear ophthalmoplegia
DEFICITMidline
Structu
res
More Info
Motor pathway(Corticospinal tract)
Medial lemniscus
Medial longditudinal fasciculus
Motor nucleus and nerve
Contalateral weakness
Contralateral propioception/ vibration
loss
Ipsilateral internuclear ophthalmoplegia
Ipsilateral CN function loss
DEFICITMidline
Structu
res
Spinocerebellar pathway
Spinothalamic
Sensory nucleus of CN5
Sympathetic pathway
Ipsilateral ataxia
DEFICITLateral
Structu
res
More Info
Spinocerebellar pathway
Spinothalamic
Sensory nucleus of CN5
Sympathetic pathway
Ipsilateral ataxia
Contralateral pain/temp sensory loss
DEFICITLateral
Structu
res
More Info
Spinocerebellar pathway
Spinothalamic
Sensory nucleus of CN5
Sympathetic pathway
Ipsilateral ataxia
Contralateral pain/temp sensory loss
Ipsilateral pain/ temp loss in face
DEFICITLateral
Structu
res
More Info
Spinocerebellar pathway
Spinothalamic
Sensory nucleus of CN5
Sympathetic pathway
Ipsilateral ataxia
Contralateral pain/temp sensory loss
Ipsilateral pain/ temp loss in face
Ipsilateral Horner’s syndrome
DEFICITLateral
Structu
res
More Info
Glossopharyngeal CN9
Vagus CN10
Spinal accessory CN11
Hypoglossal CN12
Ipsilateral pharyngeal sensory loss
DEFICIT4 CN
Medulla
Glossopharyngeal CN9
Vagus CN10
Spinal accessory CN11
Hypoglossal CN12
Ipsilateral pharyngeal sensory loss
Ipsilateral palatal weakness
DEFICIT4 CN
Medulla
More Info
Glossopharyngeal CN9
Vagus CN10
Spinal accessory CN11
Hypoglossal CN12
Ipsilateral pharyngeal sensory loss
Ipsilateral palatal weakness
Ipsilateral shoulder weakness
DEFICIT4 CN
Medulla
Glossopharyngeal CN9
Vagus CN10
Spinal accessory CN11
Hypoglossal CN12
Ipsilateral pharyngeal sensory loss
Ipsilateral palatal weakness
Ipsilateral shoulder weakness
Ipsilateral weakness of tongue
DEFICIT4 CN
Medulla
More Info
Trigeminal CN5
Abducent CN6
Facial CN7
Auditory CN8
Ipsilateral facial sensory loss
DEFICIT4 CN
Pons
More Info
Trigeminal CN5
Abducent CN6
Facial CN7
Auditory CN8
Ipsilateral facial sensory loss
Ipsilateral eye abduction weakness
DEFICIT4 CN
Pons
More Info
Trigeminal CN5
Abducent CN6
Facial CN7
Auditory CN8
Ipsilateral facial sensory loss
Ipsilateral eye abduction weakness
Ipsilateral facial weakness
DEFICIT4 CN
Pons
More Info
Trigeminal CN5
Abducent CN6
Facial CN7
Auditory CN8
Ipsilateral facial sensory loss
Ipsilateral eye abduction weakness
Ipsilateral facial weakness
Ipsilateral deafness
DEFICIT4 CN
Pons
Olfactory CN1
Optic CN2
Occulomotor CN3
Trochlear CN4
Not in midbrain
Not in midbrain
Eye turned out and down
DEFICIT4 CN
Above Pons
More Info
Olfactory CN1
Optic CN2
Occulomotor CN3
Trochlear CN4
Not in midbrain
Not in midbrain
Eye turned out and down
Eye unable to look down when looking towards nose
DEFICIT4 CN
Above Pons
More Info
Let’s put your knowledge to use...
“Pathways and tracts pass through the entire length of the brainstem and can be likened to ‘meridians of longitude‘ whereas the various cranial nerves can be regarded as ‘parallels of latitude‘. If you establish where the meridians of longitude and parallels of latitude intersect then you have established the site of the lesion.”
Always remember
Gates, P. The rule of 4 of the brainstem: a simplified method for understanding brainstem anatomy and brainstem vascular syndromes for the non-neurologist. Internal Medicine Journal 2005; 35: 263-266
58 year old woman•Left hemiparesis•Left-sided loss of propioception•Right-sided tongue deviation
Case
58 year old woman•Left hemiparesis•Left-sided loss of propioception•Right-sided tongue deviation
•Motor (CS tract, R)
•Medial lemniscus, R•CN12, R
Case Structure
•Motor (CS tract, R)
•Medial lemniscus, R•CN12, R
Structure
•Medial•Medial
•Medulla
•Motor (CS tract, R)
•Medial lemniscus, R•CN12, R
Location Structure
•Medial•Medial
•Medulla
•Motor (CS tract, R)
•Medial lemniscus, R•CN12, R
Location
Medial medullary syndrome (R)
Vertebral artery, medullary branch (R)
Structure
58 year old woman•Left-sided meiosis, anhydrosis, ptosis•Left-sided ataxia•Uvula deviated to right
Case
58 year old woman•Left-sided meiosis, anhydrosis, ptosis•Left-sided ataxia•Uvula deviated to right
•Sympathetic tract, Left
•Spinocerebellar•CN10, Left
Case Structure
•Sympathetic tract, Left
•Spinocerebellar•CN10, Left
Structure
•Side, Left
•Side, Left•Medulla
•Sympathetic tract, Left
•Spinocerebellar•CN10, Left
Location Structure
•Side, Left
•Side, Left•Medulla
•Sympathetic tract, Left
•Spinocerebellar•CN10, Left
Lateral medullary syndrome (L)
Posterior inferior cerebellar artery (L)
Location Structure
Assignment
In lateral medullary syndrome (Wallenberg syndrome), there are associated analgesia and thermoanalgesia of the ipsilateral face. Why? What brainstem structure is affected?
10 y/o girl with the ff symptoms
Case
Left-sided weakness
Right eye deviates medially
Righ-sided facial weakness
Structure
10 y/o girl with the ff symptoms
Case
Left-sided weakness
Right eye deviates medially
Righ-sided facial weakness
Motor (CS tract, R)
Structure
10 y/o girl with the ff symptoms
Case
Left-sided weakness
Right eye deviates medially
Righ-sided facial weakness
Motor (CS tract, R)
LR weakness, CN6 Right
Structure
10 y/o girl with the ff symptoms
Case
Left-sided weakness
Right eye deviates medially
Righ-sided facial weakness
Motor (CS tract, R)
LR weakness, CN6 Right
CN7, Right
Structure
Location
Motor (CS tract, R)
LR weakness, CN6 Right
CN7, Right
Structure
Location
Medial structure Motor (CS tract, R)
LR weakness, CN6 Right
CN7, Right
Structure
Location
Medial structure
Pons
Motor (CS tract, R)
LR weakness, CN6 Right
CN7, Right
Structure
Location
Medial structure
Pons
Pons
Motor (CS tract, R)
LR weakness, CN6 Right
CN7, Right
Structure
Location
Medial structure
Pons
Pons
Motor (CS tract, R)
LR weakness, CN6 Right
CN7, Right
Medial Pons Pons tumor
Structure
Location
Medial structure
Pons
Pons
Motor (CS tract, R)
LR weakness, CN6 Right
CN7, Right
Medial Pons Pons tumorMillard-Gubler Syndrome
Structure
Assignment
What is astrocytoma?Where is it usually located?Who are most often affected?
70 y/o male hypertensive suddenly developed
Case
Left-sided ipsilateral ophthalmoplegia
Loss of pupilary light reflex, left eye
Paralysis of right arm and leg
Structure
70 y/o male hypertensive suddenly developed
Case
Left-sided ipsilateral ophthalmoplegia
Loss of pupilary light reflex, left eye
Paralysis of right arm and leg
CN3, Left
Structure
70 y/o male hypertensive suddenly developed
Case
Left-sided ipsilateral ophthalmoplegia
Loss of pupilary light reflex, left eye
Paralysis of right arm and leg
CN3, Left
CN3, Left
Structure
70 y/o male hypertensive suddenly developed
Case
Left-sided ipsilateral ophthalmoplegia
Loss of pupilary light reflex, left eye
Paralysis of right arm and leg
CN3, Left
Motor, CS tract, Left
CN3, Left
Structure
Location
CN3, Left
Motor, CS tract, Left
CN3, Left
Structure
Location
Midbrain CN3, Left
Motor, CS tract, Left
CN3, Left
Structure
Location
Midbrain
Midbrain
CN3, Left
Motor, CS tract, Left
CN3, Left
Structure
Location
Midbrain
Midbrain
Medial, Left
CN3, Left
Motor, CS tract, Left
CN3, Left
Structure
Location
Midbrain
Midbrain
Medial, Left
CN3, Left
Motor, CS tract, Left
CN3, Left
Medial Midbrain Weber’s Syndrome
Structure
70 y/o male hypertensive suddenly developed
Case
Left-sided ipsilateral ophthalmoplegia
Right-sided propioception loss
Involuntary movement
Structure
70 y/o male hypertensive suddenly developed
Case
Left-sided ipsilateral ophthalmoplegia
Right-sided propioception loss
Involuntary movement
CN3, Left
Structure
70 y/o male hypertensive suddenly developed
Case
Left-sided ipsilateral ophthalmoplegia
Right-sided propioception loss
Involuntary movement
CN3, Left
Medial Lemniscus, Left
Structure
70 y/o male hypertensive suddenly developed
Case
Left-sided ipsilateral ophthalmoplegia
Right-sided propioception loss
Involuntary movement
CN3, Left
Medial Lemniscus, Left
Red nucleus, Left
Structure
CN3, Left
Medial Lemniscus, Left
Red nucleus, Left
StructureLocation
Midbrain, Left CN3, Left
Medial Lemniscus, Left
Red nucleus, Left
StructureLocation
Midbrain, Left
Medial, Left
CN3, Left
Medial Lemniscus, Left
Red nucleus, Left
StructureLocation
Midbrain, Left
Medial, Left
Medial, Left
CN3, Left
Medial Lemniscus, Left
Red nucleus, Left
StructureLocation
Midbrain, Left
Medial, Left
Medial, Left
CN3, Left
Medial Lemniscus, Left
Red nucleus, Left
Medial Midbrain Benedikt’s Syndrome
StructureLocation
Weber’s Syndrome Benedikt’s Syndrome
CN3
Medial Lemniscus
Red nucleus
CN3
Motor, CS tract
Corticobulbar tract
Medial midbrain Medial midbrain
Benedikt’sWeber’s
Parinaud’s syndrome•Posterior midbrain•Superior colliculi•Center for upward gaze•Inability to look up (Doll’s eye)•Argylle-Robertson pupil
Any questions?The End
Brain stem
90%10%
RETURN
Brain stem
90%10%
LESION
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Brain stem
90%10%
LESION
Contralateral paralysis
RETURN
Return
LESION
Return
LESION
Contralateral sensory loss
Return
Return
Return
Return
Return
LESION
Return
LESION
Ipsilateral ataxia
Brain Stem
Pain &
temperature
LESION
Contralateral sensory loss
Return
Return
LESION
Return
LESION
Ipsilateral facial sensory loss
Return
MeiosisPtosis
Anhydrosis
Horner’s Syndrome
Return
Deviated to the right
Return
Levator uvalaeVagusVagus
Return
Deviated to the right
Levator uvalaeVagusVagus
Lesion
Return
Deviated to the right
Levator uvalaeVagusVagus
Lesion
Uvula deviates OPPOSITEthe lesion
Return
Deviated to the LEFT
Tongue deviates
OPPOSITE the lesion
Return
Return
Return
Facial weakness
Return
Return
Cranial Nerve 3•EOM except lateral rectus & superior oblique•Down and out•Ptosis•Absent pupillary light reflex
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