Lecture Notes of Doctor Bravo

1. Lessons on
Brainstem
Lesions
Dr. Dennis Bravo

2. Case
A 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?

3. review
of
Brainstem Structure

4. Brainstem Anatomy
Midbrain
Pons
Medulla

5. Brainstem Anatomy
Midbrain
Pons
Medulla

6. 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

7. 1 2
4 Motor nuclei in
4 Structures in midline midline and are divisors
and begin with ‘M’ of 12
( 3, 4, 6, 12)
RULE of
FOUR*
3 4
4 CN in medulla
4 Structures to the side
4 CN in pons
and begin with ‘S’
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

8. 2
4 Motor nuclei in
4 Structures in midline midline and are divisors
and begin with ‘M’ of 12
( 3, 4, 6, 12)
3 4
4 CN in medulla
4 Structures to the side
4 CN in pons
and begin with ‘S’
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

9. 4 Motor nuclei in
4 Structures in midline midline and are divisors
and begin with ‘M’ of 12
( 3, 4, 6, 12)
3 4
4 CN in medulla
4 Structures to the side
4 CN in pons
and begin with ‘S’
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

10. 4 Motor nuclei in
4 Structures in midline midline and are divisors
and begin with ‘M’ of 12
( 3, 4, 6, 12)
4
4 CN in medulla
4 Structures to the side
4 CN in pons
and begin with ‘S’
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

11. 4 Motor nuclei in
4 Structures in midline midline and are divisors
and begin with ‘M’ of 12
( 3, 4, 6, 12)
4 CN in medulla
4 Structures to the side
4 CN in pons
and begin with ‘S’
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

12. RULE #1
4 Medial Structures
•Motor pathway
•Medial leminiscus
•Medial longitudinal
fasciculus
•Motor nucleus and nerve

13. RULE #2
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

14. RULE #3
4 Side Structures
•Spinocerebellar pathway
•Spinothalamic pathway
•Sensory nucleus of CN5
•Sympathetic pathway

15. 4 Medulla Cranial
RULE #4 Nerves
•Glossopharyngeal (CN9)
•Vagus (CN10)
•Spinal accessory (CN11)
•Hypoglossal (CN12)

16. RULE #4
4 Pons Cranial Nerves
•Trigeminal (CN5)
•Abducent (CN6)
•Facial (CN7)
•Auditory (CN8)

17. 4 Cranial Nerves
RULE #4 Above Pons
•Olfactory (CN1)
•Optic (CN2)
•Occulomotor (CN3)
•Trochlear (CN4)

18. ne s
li e
DE
id ur FIC
M ct I T
S tru
Motor pathway
Contalateral weakness
(Corticospinal tract)
More Info
Medial lemniscus
Medial longditudinal
fasciculus
Motor nucleus and
nerve

19. ne s
li e
DE
id ur FIC
M ct I T
S tru
Motor pathway
Contalateral weakness
(Corticospinal tract)
Contralateral propioception/
Medial lemniscus vibration loss
More Info
Medial longditudinal
fasciculus
Motor nucleus and
nerve

20. ne s
li e
DE
id ur FIC
M ct I T
S tru
Motor pathway
Contalateral weakness
(Corticospinal tract)
Contralateral
Medial lemniscus propioception/ vibration
loss
Medial longditudinal Ipsilateral internuclear
fasciculus ophthalmoplegia
More Info
Motor nucleus and
nerve

21. ne s
li e
DE
id ur FIC
M ct I T
S tru
Motor pathway
Contalateral weakness
(Corticospinal tract)
Contralateral
Medial lemniscus propioception/ vibration
loss
Medial longditudinal Ipsilateral internuclear
fasciculus ophthalmoplegia
Motor nucleus and Ipsilateral CN
nerve function loss

22. al DE
er es
at ur FIC
L ct IT
S tru
Spinocerebellar
Ipsilateral ataxia
pathway
More Info
Spinothalamic
Sensory nucleus of
CN5
Sympathetic pathway

23. al DE
er es
at ur FIC
L ct I T
S tru
Spinocerebellar
Ipsilateral ataxia
pathway
Contralateral pain/temp
Spinothalamic sensory loss
More Info
Sensory nucleus of
CN5
Sympathetic pathway

24. al DE
er es
at ur FIC
L ct I T
S tru
Spinocerebellar
Ipsilateral ataxia
pathway
Contralateral pain/temp
Spinothalamic sensory loss
Sensory nucleus of Ipsilateral pain/ temp
CN5 loss in face
More Info
Sympathetic pathway

25. al DE
er es
at ur FIC
L ct I T
S tru
Spinocerebellar
Ipsilateral ataxia
pathway
Contralateral pain/temp
Spinothalamic sensory loss
Sensory nucleus of Ipsilateral pain/ temp
CN5 loss in face
Ipsilateral Horner’s
Sympathetic pathway
syndrome
More Info

26. DE
CN lla
4 u
FIC
I T
ed
M
Glossopharyngeal Ipsilateral pharyngeal
CN9 sensory loss
Vagus CN10
Spinal accessory CN11
Hypoglossal CN12

27. DE
CN lla
4 u
FIC
I T
ed
M
Glossopharyngeal Ipsilateral pharyngeal
CN9 sensory loss
Ipsilateral palatal
Vagus CN10
weakness
More Info
Spinal accessory CN11
Hypoglossal CN12

28. DE
CN lla
4 u
FIC
I T
ed
M
Glossopharyngeal Ipsilateral pharyngeal
CN9 sensory loss
Ipsilateral palatal
Vagus CN10
weakness
Ipsilateral shoulder
Spinal accessory CN11
weakness
Hypoglossal CN12

29. DE
CN lla
4 u
FIC
I T
ed
M
Glossopharyngeal Ipsilateral pharyngeal
CN9 sensory loss
Ipsilateral palatal
Vagus CN10
weakness
Ipsilateral shoulder
Spinal accessory CN11
weakness
Ipsilateral weakness of
Hypoglossal CN12
tongue
More Info

30. DE
CN
4 ns
FIC
IT
Po
Ipsilateral facial
Trigeminal CN5
sensory loss
More Info
Abducent CN6
Facial CN7
Auditory CN8

31. DE
CN
4 ns
FIC
IT
Po
Ipsilateral facial
Trigeminal CN5
sensory loss
Ipsilateral eye
Abducent CN6
abduction weakness
More Info
Facial CN7
Auditory CN8

32. DE
CN
4 ns
FIC
IT
Po
Ipsilateral facial
Trigeminal CN5
sensory loss
Ipsilateral eye
Abducent CN6
abduction weakness
Ipsilateral facial
Facial CN7
weakness
More Info
Auditory CN8

33. DE
CN
4 ns
FIC
IT
Po
Ipsilateral facial
Trigeminal CN5
sensory loss
Ipsilateral eye
Abducent CN6
abduction weakness
Ipsilateral facial
Facial CN7
weakness
Auditory CN8 Ipsilateral deafness

34. DE
4 CN ons FIC
P IT
ve
A bo
Olfactory CN1 Not in midbrain
Optic CN2 Not in midbrain
Eye turned out and
Occulomotor CN3
down
More Info
Trochlear CN4

35. DE
4 CN ons FIC
P I T
ve
A bo
Olfactory CN1 Not in midbrain
Optic CN2 Not in midbrain
Eye turned out and
Occulomotor CN3
down
Eye unable to look down
Trochlear CN4 when looking towards nose
More Info

36. Let’s put your
knowledge to use...

37. Always remember
“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.”
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

38. Case
58 year old woman
•Left hemiparesis
•Left-sided loss of
propioception
•Right-sided
tongue deviation

39. Case Structure
58 year old woman
•Left hemiparesis •Motor (CS tract, R)
•Left-sided loss of •Medial
propioception lemniscus, R
•Right-sided •CN12, R
tongue deviation

40. Structure
•Motor (CS tract, R)
•Medial
lemniscus, R
•CN12, R

41. Location Structure
•Medial •Motor (CS tract, R)
•Medial •Medial
lemniscus, R
•Medulla •CN12, R

42. Location Structure
•Medial •Motor (CS tract, R)
•Medial •Medial
lemniscus, R
•Medulla •CN12, R
Medial medullary Vertebral artery,
syndrome (R) medullary branch (R)

43. Case
58 year old woman
•Left-sided
meiosis,
anhydrosis, ptosis
•Left-sided ataxia
•Uvula deviated
to right

44. Case Structure
58 year old woman
•Left-sided •Sympathetic
meiosis, tract, Left
anhydrosis, ptosis
•Left-sided ataxia •Spinocerebellar
•Uvula deviated •CN10, Left
to right

45. Structure
•Sympathetic
tract, Left
•Spinocerebellar
•CN10, Left

46. Location Structure
•Side, Left •Sympathetic
tract, Left
•Side, Left •Spinocerebellar
•Medulla •CN10, Left

47. Location Structure
•Side, Left •Sympathetic
tract, Left
•Side, Left •Spinocerebellar
•Medulla •CN10, Left
Lateral medullary Posterior inferior
syndrome (L) cerebellar artery (L)

48. Assignment
In lateral medullary syndrome
(Wallenberg syndrome), there are
associated analgesia and
thermoanalgesia of the ipsilateral
face. Why? What brainstem
structure is affected?

49. Case Structure
10 y/o girl
with the ff symptoms
Left-sided weakness
Right eye deviates medially
Righ-sided facial weakness

50. Case Structure
10 y/o girl
with the ff symptoms
Left-sided weakness Motor (CS tract, R)
Right eye deviates medially
Righ-sided facial weakness

51. Case Structure
10 y/o girl
with the ff symptoms
Left-sided weakness Motor (CS tract, R)
Right eye deviates medially LR weakness, CN6 Right
Righ-sided facial weakness

52. Case Structure
10 y/o girl
with the ff symptoms
Left-sided weakness Motor (CS tract, R)
Right eye deviates medially LR weakness, CN6 Right
Righ-sided facial weakness CN7, Right

53. Location Structure
Motor (CS tract, R)
LR weakness, CN6 Right
CN7, Right

54. Location Structure
Medial structure Motor (CS tract, R)
LR weakness, CN6 Right
CN7, Right

55. Location Structure
Medial structure Motor (CS tract, R)
Pons LR weakness, CN6 Right
CN7, Right

56. Location Structure
Medial structure Motor (CS tract, R)
Pons LR weakness, CN6 Right
Pons CN7, Right

57. Location Structure
Medial structure Motor (CS tract, R)
Pons LR weakness, CN6 Right
Pons CN7, Right
Medial Pons Pons tumor

58. Location Structure
Medial structure Motor (CS tract, R)
Pons LR weakness, CN6 Right
Pons CN7, Right
Medial Pons Pons tumor
Millard-Gubler Syndrome

59. Assignment
What is astrocytoma?
Where is it usually located?
Who are most often affected?

60. Case Structure
70 y/o male hypertensive
suddenly developed
Left-sided ipsilateral
ophthalmoplegia
Loss of pupilary light reflex, left
eye
Paralysis of right arm and leg

61. Case Structure
70 y/o male hypertensive
suddenly developed
Left-sided ipsilateral
ophthalmoplegia CN3, Left
Loss of pupilary light reflex, left
eye
Paralysis of right arm and leg

62. Case Structure
70 y/o male hypertensive
suddenly developed
Left-sided ipsilateral
ophthalmoplegia CN3, Left
Loss of pupilary light reflex, left
eye CN3, Left
Paralysis of right arm and leg

63. Case Structure
70 y/o male hypertensive
suddenly developed
Left-sided ipsilateral
ophthalmoplegia CN3, Left
Loss of pupilary light reflex, left
eye CN3, Left
Paralysis of right arm and leg Motor, CS tract, Left

64. Location Structure
CN3, Left
CN3, Left
Motor, CS tract, Left

65. Location Structure
Midbrain CN3, Left
CN3, Left
Motor, CS tract, Left

66. Location Structure
Midbrain CN3, Left
Midbrain CN3, Left
Motor, CS tract, Left

67. Location Structure
Midbrain CN3, Left
Midbrain CN3, Left
Medial, Left Motor, CS tract, Left

68. Location Structure
Midbrain CN3, Left
Midbrain CN3, Left
Medial, Left Motor, CS tract, Left
Medial Midbrain Weber’s Syndrome

69. Case Structure
70 y/o male hypertensive
suddenly developed
Left-sided ipsilateral
ophthalmoplegia
Right-sided propioception loss
Involuntary movement

70. Case Structure
70 y/o male hypertensive
suddenly developed
Left-sided ipsilateral
ophthalmoplegia CN3, Left
Right-sided propioception loss
Involuntary movement

71. Case Structure
70 y/o male hypertensive
suddenly developed
Left-sided ipsilateral
ophthalmoplegia CN3, Left
Right-sided propioception loss Medial Lemniscus, Left
Involuntary movement

72. Case Structure
70 y/o male hypertensive
suddenly developed
Left-sided ipsilateral
ophthalmoplegia CN3, Left
Right-sided propioception loss Medial Lemniscus, Left
Involuntary movement Red nucleus, Left

73. Location Structure
CN3, Left
Medial Lemniscus, Left
Red nucleus, Left

74. Location Structure
Midbrain, Left CN3, Left
Medial Lemniscus, Left
Red nucleus, Left

75. Location Structure
Midbrain, Left CN3, Left
Medial, Left Medial Lemniscus, Left
Red nucleus, Left

76. Location Structure
Midbrain, Left CN3, Left
Medial, Left Medial Lemniscus, Left
Medial, Left Red nucleus, Left

77. Location Structure
Midbrain, Left CN3, Left
Medial, Left Medial Lemniscus, Left
Medial, Left Red nucleus, Left
Medial Midbrain Benedikt’s Syndrome

78. Weber’s Syndrome Benedikt’s Syndrome
CN3 CN3
Motor, CS tract Medial Lemniscus
Corticobulbar tract Red nucleus
Medial midbrain Medial midbrain

79. Weber’s Benedikt’s

80. Parinaud’s syndrome
•Posterior midbrain
•Superior colliculi
•Center for upward
gaze
•Inability to look up
(Doll’s eye)
•Argylle-Robertson
pupil

81. Any questions?
The End

82. RETURN
Brain stem
10% 90%

83. RETURN
LESION Brain stem
10% 90%

84. RETURN
LESION Brain stem
10% 90%
Contralateral
paralysis

85. Return

86. Return
LESION

87. Return
LESION
Contralateral
sensory loss

88. Return

89. Return

90. Return

91. Return
LESION

92. Return
LESION
Ipsilateral
ataxia

93. Return
LESION Brain Stem
Contralateral
sensory loss
Pain
&
temperature

94. Return

95. Return
LESION

96. Return
LESION
Ipsilateral facial
sensory loss

97. Horner’s Syndrome
Meiosis
Ptosis
Anhydrosis
Return

98. Deviated
to the right
Return

99. Vagus Vagus
Levator uvalae
Return

100. Vagus Vagus
Levator uvalae
Lesion
Deviated
to the right
Return

101. Vagus Vagus
Levator uvalae
Lesion
Deviated
to the right
Uvula deviates
OPPOSITEthe lesion
Return

102. Tongue
deviates
OPPOSITE the
lesion
Deviated
to the LEFT
Return

103. Return

104. Return

105. Facial weakness
Return

106. Cranial Nerve 3
•EOM except lateral
rectus & superior
oblique
•Down and out
•Ptosis
•Absent pupillary
light reflex
Return

107. Return