Full story brain herniation imaging Dr Ahmed Esawy include different cases for oral radiodiagnosis examination all over the world CT /MRI Plain X ray images I Supratentorial herniation 1-Cingulate (subfalcine/transfalcine) 2-Uncal (descending transtentorial herniation DTH) 3-Central (bilateral DTH) 4-Transcalvarial 5-Tectal (posterior) II-Infratentorial herniation 1-Upward (upward cerebellar or upward transtentorial) 2-Tonsillar (downward cerebellar III-Sphenoid/alar herniation Transalar Herniation

1. IMAGING
BRAIN HERNIATION
Dr. Ahmed Esawy
MBBS M.Sc. MD
Dr Ahmed Esawy

2. CLASSIFICATION BRAIN HERNAITION
I Supratentorial herniation
1-Cingulate (subfalcine/transfalcine)
2-Uncal (descending transtentorial herniation DTH)
3-Central (bilateral DTH)
4-Transcalvarial
5-Tectal (posterior)
II-Infratentorial herniation
1-Upward
(upward cerebellar or upward transtentorial)
2-Tonsillar (downward cerebellar
III-Sphenoid/alar herniation Transalar Herniation
Dr Ahmed Esawy

3. Brain herniation
A brain herniation is when brain tissue, cerebrospinal fluid, and blood vessels are moved or
pressed away from their usual position inside the skull.
Causes
Brain herniation occurs when something inside the skull produces pressure that moves brain
tissues. This is most often the result of brain swelling from a
•head injury, stroke
•or brain tumor.
Brain herniation can be a side effect of tumors in the brain, including:
Metastatic brain tumor
Primary brain tumour (brain tumours,meningioma,base of skull tumours,
suprasellar tumours
Herniation of the brain can also be caused by other factors that lead to increased pressure
inside the skull, including:
•Abscess
•Hemorrhage (intracerebral ,subdural ,extradual)
•Hydrocephalus
•Strokes that cause brain swelling
•Swelling after radiation therapy
Dr Ahmed Esawy

4. Pathology of Increased Intracranial Pressure
 Increased intracranial pressure (ICP): - if > 40
mm Hg  cerebral hypoxia, cerebral ischemia,
cerebral edema, hydrocephalus, and brain
herniation.
 Cerebral edema: Edema - Disruption of the blood
brain barrier – vasodilatation – swelling.
 Hydrocephalus  communicating type common
inTotal Body Irradiation.
Dr Ahmed Esawy

5. Dr Ahmed Esawy

6. Dr Ahmed Esawy

7. Cingulate herniation
(subfalcine/transfalcine)
Dr Ahmed Esawy

8. Cingulate herniation
(subfalcine/transfalcine)
Subfalcine herniation on CT
In cingulate or subfalcine herniation, the most common type, the
innermost part of the frontal lobe is scraped under part of the falx cerebri,
the dura mater at the top of the head between the two hemispheres of the
brain
Cingulate herniation can be caused when one hemisphere swells and pushes
the cingulate gyrus by the falx cerebri
cingulate herniation may present with abnormal posturing and coma
Dr Ahmed Esawy

9. the cingulate gyrus lies on the medial aspect
of the cerebral hemisphere. It forms a major
part of the limbic system which has functions
in emotion and behaviour.The frontal
portion is termed the anterior cingulate gyrus
(or cortex)
Dr Ahmed Esawy

10. Subfalcine herniation
most common
•supratentorial mass in one hemicranium
•affected hemisphere pushes across the midline under the inferior "free" margin
of the falx, extending into the contralateral hemicranium
Subfalcine herniation: imaging
Axial and coronal images show that
•cingulate gyrus
•anterior cerebral artery (ACA)
•internal cerebral vein (ICV)
are pushed from one side to the other under the falx cerebri.
The ipsilateral ventricle appears compressed and displaced across the midline
Dr Ahmed Esawy

11. Subfalcine herniation
Complications
• unilateral obstructive hydrocephalus
–foramen of Monro occlusion
•Periventricular hypodensity with "blurred" margins of the lateral ventricle
–Fluid accumulates in the periventricular white matter
•When severe, the herniating ACA can be pinned against the inferior "free" margin of
the falx cerebri
• secondary infarction of the cingulate gyrus
Dr Ahmed Esawy

12. Dr Ahmed Esawy

13. Subfalcine herniation
from acute SDH
Dr Ahmed Esawy

14. acute on chronic subdural hematoma.
Subfalcine herniation, midline shift, effacement of the ipsilateral lateral ventricle, and
enlargement of the contralateral occipital horn are present.
Dr Ahmed Esawy

15. Coronal contrast-enhancedTi-weighted image of patient with metastatic breast cancer.
Coronal MR imaging accurately shows ipsilateral cingulate gyrus (asterisk) displaced
beneath falx with depression of corpus callosum.There is compression of contralateral
cingulate gyrus (straight arrow) and corpus callosum. Pencailosal artery (curved arrow) is
displaced beneath falx. Lateral and third ventricles are also displaced.
subfaicine herniation.
Dr Ahmed Esawy

16. Degrees of subfalcine herniation.
A, Axial CT scan of right parietal posttraumatic hemorrhage and subdural hematoma
(arrowheads). some compression of right lateral ventricle is present, with shift to left asso-
ciated with mild deviation of anterior faix (arrow).
B, Axial CT scan of massive right infarct. Right lateral ventricle is compressed and markedly
displaced to opposite side. Note that posterior falx remains non displaced despite massive
shift including anterior faix (arrow) Dr Ahmed Esawy

17. Paradoxical herniation
The postoperative CT image shows evidence of
left craniectomy with a small amount of
residual subdural fluid collection and blood.
A repeat CT image upon returning after 4
months shows resolution of the subdural fluid
collection and blood
after 4 months there is interval demonstration of concave deformity of the left cerebral
hemisphere together with the overlying skin flap, with associated distortion of the left
ventricle and a new left subfalcine paradoxical herniationDr Ahmed Esawy

18. the tentorium is a structure within
the skull formed by the dura mater of the
meninges
Transtentorial herniation can occur when
the brain moves either up or down across
the tentorium, called ascending and
descending transtentorial herniation
respectively; however descending
herniation is much more common
Dr Ahmed Esawy

19. Uncal herniation
(Descending transtentorial herniations )
Dr Ahmed Esawy

20. Descending transtentorial herniation types
•Unilateral
•Bilateral ("central“) Severe
Dr Ahmed Esawy

21. Uncal herniation
(Descending transtentorial herniations )
In uncal herniation, a common subtype of transtentorial herniation, the
innermost part of the temporal lobe, the uncus, can be squeezed so
much that it moves towards the tentorium and puts pressure on
the brainstem, most notably the midbrain
Dr Ahmed Esawy

22. The uncus is an anterior extremity of
the Parahippocampal gyrus. It is separated
from the apex of the temporal lobe by a slight
fissure called the incisura temporalis.
Dr Ahmed Esawy

23. Dr Ahmed Esawy

24. Dr Ahmed Esawy

25. Parietal lobe
Superior temporal gyrus
Middle temporal gyrus
Pons
Medulla oblongata
Cerebral peduncle
Centrum semiovale
3rd ventricle
Inferior temporal gyrus
Petrous ridge of temporal bone
Parahippocampal gyrus
Dr Ahmed Esawy

26. Pontine cistern
pre-pontine cistern
• Anterior to the pons.Location
• Basilar A.
• AICA.
• Ant. Pontomesencephalic V.
• Cn 5.
• Cn 6.
Contents
Dr Ahmed Esawy

27. Pontine cistern
Dr Ahmed Esawy

28. Pontine cistern
Basilar A
Ant. PontomesencephalicV
PetrosalV
Superior petrosal sinus
Dr Ahmed Esawy

29. Pontine cistern
Dr Ahmed Esawy

30. Pontine cistern
AICA
BA
Cn6 Cn6
BA
Dr Ahmed Esawy

31. Perimesencephalic cistern
1. Interpeduncular C.
2. Crural C.
3. Ambient C.
4. Quadrigeminal C.
Dr Ahmed Esawy

32. Quadrigeminal cistern
vein of Galen cistern
• Posterior to the
quadrigeminal plate,
• Inferior to the splenium of
corpus callosum &
• Superior to the
cerebellum
Location
• Vein of Galen .
• PrecentralV.
• P3 of PCA.
Contents
Dr Ahmed Esawy

33. Dr Ahmed Esawy

34. Chiasmatic cistern
Suprasellar cistern
• Above the sella.Location
• Optic chiasm.
• Pituitary
infundibulum
Contents
Dr Ahmed Esawy

35. CP angle cistern
AICA
Dr Ahmed Esawy

36. Superior CP angle cistern
AICA
AICA
AICA
AICA
Dr Ahmed Esawy

37. Inferior CP angle cistern
Cn
9/10
Cn 10
Cn 9
Dr Ahmed Esawy

38. Uncal herniation
(Descending transtentorial herniations)
the second most common
•a hemispheric mass
•initially produces subfalcine herniation
•As the mass effect increases, the uncus of the temporal lobe is pushed medially
begins to encroach on the suprasellar cistern
hippocampus follows
hippocampus effaces the ipsilateral quadrigeminal cistern
both the uncus and hippocampus herniate inferiorly through the tentorial incisura
Dr Ahmed Esawy

39. Uncal herniation
(Descending transtentorial herniations )
The uncus can squeeze the oculomotor nerve (a.k.a.CN III), which may
affect the parasympathetic input to the eye on the side of the affected
nerve
Compression of the ipsilateral posterior cerebral artery
Duret hemorrhages (tearing of small vessels in the parenchyma) in the
median and paramedian zones of the mesencephalon and pons
The sliding uncus syndrome represents uncal herniation without
alteration in the level of consciousness and other sequelae mentioned
above.
Dr Ahmed Esawy

40. Dr Ahmed Esawy

41. Descending transtentorial herniation
As DTH increases
hippocampus also herniates medially
quadrigeminal cistern compression
midbrain pushed toward the opposite side of the incisura
Descending transtentorial herniation
severe cases
entire suprasellar and quadrigeminal cisterns are effaced.
The temporal horn can even be displaced almost into the midline
Dr Ahmed Esawy

42. Brain herniation.
1, subfalcine; 2, herniation of the uncus and hippocampal gyrus of the temporal lobe
into the tentorial notch, causing pressure on the third nerve and mid-brain; 3,
brainstem caudally; 4, cerebellar tonsils through foramen magnum.
Dr Ahmed Esawy

43. Uncal herniation is when the medial portion of the anterior temporal lobe is shifted into the
suprasellar cistern. It is a subset of descending transtenorial herniation, which is when the
cerebral hemisphere crosses the tentorium at the level of the incisura. It can result in Infarct in
the PCA distribution
Dr Ahmed Esawy

44. Dr Ahmed Esawy

45. Dr Ahmed Esawy

46. A large right frontotemporal subdural hematoma is exerting mass effect on the right
frontal and temporal lobes, with resultant effacement of the suprasellar cistern and with
right-sided uncal herniation.
effaces the ipsilateral temporal horn,
causing dilatation of the contralateral
temporal horn. Subfalcine herniation
and narrowing of the contralateral
ambient and quadrigeminal plate
cisterns are present.
Dr Ahmed Esawy

47. Acute-on-chronic right temporal subdural hematoma exerts mass effect on the right
temporal lobe, causing ipsilateral temporal horn, with effacement and dilatation of the
contralateral temporal horn. Narrowing of the contralateral ambient and quadrigeminal
plate cisterns is present, with ipsilateral widening of the ambient and quadrigeminal
cisterns.
Dr Ahmed Esawy

48. Duret hemorrhage with cerebral herniation. Large left holohemispheric and parafalcine
subdural hematoma (short black arrows, a) results in midline shift (long black arrow, a) and
uncal (long white arrow, b) herniation. Downward brainstem herniation has led to classic
Duret hemorrhage (short white arrow, b) in the paramedian midbrain
Dr Ahmed Esawy

49. descending transtentorial herniation. A-C, Axial diagram (A ), axial CT scan (B), and axialT2-
weighted MR image (C) show components of left unilateral descending transtentorial
herniation (straight arrows). Brainstem is rotated and displaced to opposite side and
caudally, producing widening of ipsilateral ambient cistern (curved arrows). Compression of
neck of contralateral temporal horn results in its dilatation (asterisk
Dr Ahmed Esawy

50. Descending transtentonal herniation. A and B, Coronal diagram (A) and coronalTi-
weighted MR Image (B) show components of left unilateral descending transtentorial
herniation (curved arrows). MR image shows extent of herniation across tentorium and
deviation of brainstem.
Dr Ahmed Esawy

51. Dr Ahmed Esawy

52. bilateral DTH
both hemispheres become swollen
the whole central brain is flattened against the skull base
All the basal cisterns are obliterated
hypothalamus and optic chiasm are crushed against the sella turcica
Dr Ahmed Esawy

53. Central herniation(bilateral DTH)
In central herniation, the diencephalon and parts of the temporal lobes of
both of the cerebral hemispheres are squeezed through a notch in
the tentorium cerebelli.
Radiographically, downward herniation is characterized by obliteration
of the suprasellar cistern from temporal lobe herniation into the
tentorial hiatus with associated compression on the cerebral peduncles.
Upwards herniation, on the other hand, can be radiographically
characterized by obliteration of the quadrigeminal cistern. Intracranial
hypotension syndrome has been known to mimic downwards
transtentorial herniation.
Dr Ahmed Esawy

54. Complete bilateral DTH
both temporal lobes herniate medially into the tentorial hiatus
midbrain and pons displaced inferiorly through the tentorial incisura
The angle between the midbrain and pons
is progressively reduced from 90° to almost 0°
Dr Ahmed Esawy

55. Complete bilateral DTH
Complications
•CN III (oculomotor) nerve compression
–CN III palsy
•PCA occlusion as it passes back up over the medial edge of the tentorium
–secondary PCA (occipital) infarct
Duret hemorrhage
diabetes insipidus due to the compression of the pituitary stalk
Dr Ahmed Esawy

56. Dr Ahmed Esawy

57. BILateral descending transtentorlal herniation. Axial CT scan reveals bilateral
descending transtentorial herniation with obliteration of perimesencephalic
cisterns. Dorsal midbrain is compressed and dongated anteroposteriorly, causing
pear-shaped deformity (asterisk) Dr Ahmed Esawy

58. Nine-year-old boy with diffuse cerebral edema and central herniation secondary to
treatment of DKA Juvenile Diabetic Ketoacidosis
.
A, Axial noncontrast CT scan shows diffuse cerebral edema with effacement of sulci and
basal cisterns.
B, Axial noncontrast CT scan obtained 2 days after A shows marked low-density infarcts in
the gyrus recti and medial orbital gyri (arrows), globus pallidi,
hippocampi/parahippocampal gyri, hypothalamus, midbrain, and posterior right temporal
lobe.
Dr Ahmed Esawy

59. C–D, Axial noncontrastT2-weighted (4000/105/1) (C) and coronal postcontrastT1-weighted
SPGR (14.4/3.7/1) (D) MR images obtained 24 days after A show cavitary infarcts in the gyrus
recti and medial orbital gyri (arrows), medial temporal lobes, midbrain and thalami.
Enhancement is present within the thalamic and midbrain lesions.There is diffuse cerebral
atrophy.
Dr Ahmed Esawy

60. Kernohan notch
•Kernohan notch phenomenon is an imaging finding
resulting from extensive midline shift due to mass effect,
resulting in indentation in the contralateral cerebral crus by
the tentorium cerebelli.This has also been referred to
as Kernohan-Woltman notch phenomenon and false
localising sign.
As the herniating temporal lobe pushes the midbrain
toward the opposite side of the incisura
contralateral cerebral peduncle is forced against the hard
edge of the tentorium
Pressure ischemia ipsilateral hemiplegia
the "false localizing" sign
Dr Ahmed Esawy

61. Dr Ahmed Esawy

62. Dr Ahmed Esawy

63. subfalcine and downward transtentorial
Kernohan phenomenon
Dr Ahmed Esawy

64. flair T1
T1+C
subfalcine and downward transtentorial
Kernohan phenomenon
Dr Ahmed Esawy

65. T1+C
FLAIR
T2
T2
ASTROCYTOMA
GII
DOWNWARD
TRANTENTORAIL
HERNIATION
Dr Ahmed Esawy

66. Uncal herniation with Kernohan phenomenon
Dr Ahmed Esawy

67. Dr Ahmed Esawy

68. Dr Ahmed Esawy

69. Dr Ahmed Esawy

70. Dr Ahmed Esawy

71. Dr Ahmed Esawy

72. complications of transtentorial herniation. Midbrain (Duret’s) hemorrhage.
Axial CT scan of patient with head trauma reveals left transtentorial herniation
with deformity of brainstem. Midline hemorrhage is seen within upper pons
(arrow) caused by herniation
Dr Ahmed Esawy

73. Infratentorial herniation
DESCENDINGTONSILLAR HERNIATION
ASCENDINGTRANSTENTORIAL HERNIATION
Dr Ahmed Esawy

74. Tentorial incisure(also known as the tentorial notch or incisura tentorii) to
the anterior opening between the free edge of the tentorium cerebelli and theclivus for
the passage of the brainstem.
It's located between the tentorial edges and communicates
the supratentorial and infratentorial spaces
Tentorial incisure seen from above
The propensity of tonsillar herniation to
follow descending tentorial herniation is
related to the size and shape of the incisura.
If the incisura is small, the patient will be
less likely to have tonsillar herniation
Dr Ahmed Esawy

75. DownwardTonsillar herniation
In tonsillar herniation, also called downward cerebellar herniation] transforaminal
herniation, or "coning", the cerebellar tonsils move downward through
the foramen magnum possibly causing compression of the lower brainstem and
upper cervical spinal cord
Tonsillar herniation of the cerebellum is also known as a Chiari
malformation (CM),
Cerebellar tonsillar ectopia (CTE) is a term used by radiologists to describe
cerebellar tonsils that are "low lying"
Dr Ahmed Esawy

76. DescendingTonsillar herniation
•The cerebellar tonsils are displaced inferiorly and become impacted into the foramen
magnum.
•congenital (e.g.,Chiari 1 malformation)
– mismatch between size and content of the posterior fossa
•Acquired
–an expanding posterior fossa mass (tumour, haemorrhage,stroke, abscess) pushing
the tonsils downward—more common
–intracranial hypotension: abnormally low intraspinal CSF pressure
tonsils are pulled downward
Diagnosing
tonsillar herniation on NECT scans may be problematic.
Cisterna magna obliteration
Dr Ahmed Esawy

77. life threatening tonsillar herniation exerting mass effect on
the brain parenchyma can displace the posterior cranial
fossa structures inferiorly. In doing so the brainstem is
compressed against the clivus thereby altering the vital life-
sustaining functions of the pons and medulla, such as the
respiratory and cardiac centres.
Non-life threatening tonsillar descent can bee seen in
conditions such as Chiari malformations
Dr Ahmed Esawy

78. SagittalT1-weighted magnetic resonance
image of the brain. Anatomic landmarks
identified include
the fourth ventricle (A),
basion (B),
medulla oblongata (C),
cerebellar tonsil (D),
opisthion (E),
cerebellar hemisphere (F).
Dr Ahmed Esawy

79. he distance is measured by drawing a line from the inner margins foramen magnum
(basion to opisthion), and measuring the inferior most part of the tonsils
As is to be expected, values used vary somewhat from author to author
above foramen magnum: normal
<5 mm: also normal but the term benign
tonsillar ectopia can be used
>5 mm: Chiari 1 malformation
Dr Ahmed Esawy

80. -A, Drawing showing basion (B), opisthion (0), and cerebellar tonsil (T) in a
normal patient. B, Midline sagittal section, SE 500/40, showing line from basion
to opisthion in a nomal patient. Measurements were from this
Dr Ahmed Esawy

81. reference line. Bottoms of tonsils have a normal, rounded appearance and CSF is seen in a
normal cisterna magna.
Dr Ahmed Esawy

82. Coronal SE 700/40 through medulla and tonsils.The lower limits of foramen
magnum are difficult to identify. Coronal scans were not used for this reason.
Dr Ahmed Esawy

83. DescendingTonsillar herniation
MR: much more easily diagnosed
•In the sagittal plane
–the tonsillar folia become vertically oriented
–the inferior aspect of the tonsils becomes pointed
–Tonsils > 5 mm (or 7 mm in children) below the foramen magnum are generally abnormal
especially if they are peg-like or pointed (rather than rounded)
In the axial plane,T2 scans show that the tonsils are impacted into the foramen magnum
–obliterating CSF in the cisterna magna
–displacing the medulla anteriorly
Complications
•obstructive hydrocephalus
•tonsillar necrosis
Dr Ahmed Esawy

84. Dr Ahmed Esawy

85. Normal anatomy of the cerebellum (left). Chiari I malformation (right). With the size of
the posterior fossa too small, the cerebellar tonsils may herniate through the skull into
the spinal canal.The tonsils block the flow of CSF (blue) and may cause fluid buildup
inside the spinal cord, called a syrinx.
Dr Ahmed Esawy

86. A, Midline sagittal SE 500/40 scan in a
symptomatic patient.Tonsils extend 1.1
cm below foramen magnum.Tonsils are
"pointed" and cisterna magna is
obliterated.The latter two findings were
seen in both asymptomatic
symptomatic patients with low tonsils. B,
Midline sagittal SE 500/40 scan after
decompression via suboccipital craniectomy.
Tonsils now have a normal rounded
appearance.
Dr Ahmed Esawy

87. Typical MRI manifestation of brain sagging.MidsagittalT1-weighted MRI shows downward
displacement of the cerebellar tonsil by 5 mm (arrow).
brain sagging, which was
defined as either cerebral
aqueduct displacement ≥1.8
mm or cerebellar tonsil
displacement ≥4.3 mm
subdural haematoma in
patients with spontaneous
intracranial hypotension.
Dr Ahmed Esawy

88. Typical MRI manifestation of the venous distension sign.T1-weighted MRI through the
midportion of the dominant transverse sinus shows the venous distension sign (box)
subdural haematoma in patients
with spontaneous intracranial
hypotension.
Dr Ahmed Esawy

89. An MRI of the brain shows the cerebellar
tonsils (arrow) herniating through the
foramen magnum (yellow line).
Dr Ahmed Esawy

90. Dr Ahmed Esawy

91. Dr Ahmed Esawy

92. With a loss in CSF volume, there is a greater increase in blood volume.This
results in dural venous hyperemia and pachymeningeal venous engorgement
and edema, which can be identified on MR imaging as diffuse
pachymeningeal enhancement.
Furthermore, the decrease in volume of the suspending CSF results in
downward descent of the brain and can cause descending central
transtentorial herniation and tonsillar herniation.
A blood patch or surgical repair of the dural defect is usually required.
Dr Ahmed Esawy

93. Intracranial hypotension. (A) Coronal enhancedT1-weighted MR image demonstrates
diffuse pachymeningeal enhancement (arrows) in a patient with severe postural headaches.
(B) Sagittal enhancedT1-weighted NM image reveals tonsillar herniation (arrow),
descending transtentorial herniation (note downward descent of the brainstem, loss of
surrounding CSF spaces and flattening of the pons against the clivus) and pachymeningeal
enhancement (arrowheads). (C) Postmyelogram CT scan of the thoracic spine shows an
extradural accumulation of contrast (arrow) within die spinal canal consistent with a CSF
leak.The extradural and intradural confluent medium outlines the dura (arrowhead) at the
T10 level. A blood patch performed at this level resulted in resolution of the patient's
symptoms. Dr Ahmed Esawy

94. Tonsillar herniation. Sagittal enhancedT I -weighted MR image demonstrates a large
enhancing cerebellar mass causing both tonsillar herniation and ascending
transtentorial herniation. Note the inferior displacement of the tonsils (arrow) below
the foramen magnum and the effacement of the surrounding CSF spaces.The
brainstem is compressed and displaced against the clivus and there is upward
displacement of the superior cerebellar vermis (arrowhead) through the incisura.Dr Ahmed Esawy

95. Dr Ahmed Esawy

96. Foramen magnum/tonsillar herniation
child with a history of an Arnold-Chiari I
malformation. Image shows tonsillar
herniation with compression of the central
canal at the craniocervical junction and
resultant syringohydromyelia in the visualized
portion of the cervical spinal cord.
T2-. through the cervical spine was obtained in the
same patient as in the previous image.The cerebellar
tonsils are projecting inferiorly below the level of the
opisthion, with compression of the central canal at
the craniocervical junction. Hyperintense
syringohydromyelia in the visualized portion of the
cervical spinal cord is demonstrated.Dr Ahmed Esawy

97. tonsiliar herniation and ascending transtentorial herniation. A, SagittalTi -weighted MR image
of patient with cerebellar astrocytoma. Cerebeliar tonsils are displaced through foramen
magnum, compressing medulla and upper cervical cord. Note that there is also ascending
transtentorial herniation with tentorium bowed superiorly (curved arrow). B,Axial contrast-
enhancedTi-weighted MR image shows cerebeliar tonsils (asterisks) displaced into foramen
magnum Dr Ahmed Esawy

98. ASCENDINGTRANSTENTORIAL
HERNIATION
Dr Ahmed Esawy

99. Upward herniation
Increased pressure in the posterior fossa can
cause the cerebellum to move up through the
tentorial opening in upward, or cerebellar
herniation.The midbrain is pushed through the
tentorial notch
Dr Ahmed Esawy

100. Ascending transtentorial herniation
caused by any expanding posterior fossa mass
Neoplasms > trauma
Dr Ahmed Esawy

101. MR and CT findings of ascending transtentorial herniation include
Effacement of the superior cerebellar cistern
superior displacement of the superior vermis through the incisura
compression of the midbrain
forward displacement of the pons against the clivus
. can compress the posterior cerebral artery or superior cerebellar arteries
against the tentorium, resulting in infarctions
can compress the aqueduct of Sylvius, resulting in hydrocephalus.
Obstruction of venous outflow by compression of the vein of Galen and
basal vein of Rosenthal may occur and further
increase intracranial pressure.
Dr Ahmed Esawy

102. (5) ascending transtentorial
Dr Ahmed Esawy

103. Ascending transtentorial herniation. (A) AxialT I - weighted MR image and (B) sagittal
enhancedT I -weighted MR image demonstrate ascending transtentorial herniation in a
patient with a cerebellar lung metastases. Note the upward displacement of the superior
cerebellar vermis (black arrows) through the incisura, compression of the fourth
ventricle, and anterior displacement of the pons (arrowhead) against the clivus.
Dr Ahmed Esawy

104. Ascending transtentorial herniation
Right parasagittal gadolinium-enhancedT1-weighted
magnetic resonance image in a 9-year-old girl with a history
of right cerebellar astrocytoma who presented with
headaches and vomiting. Heterogeneously enhancing mass
is demonstrated in the right cerebellum, with compression
of the adjacent brainstem and fourth ventricle. Ascending
transtentorial herniation of the cerebellum is demonstrated
through the incisura. Descending tonsillar herniation also is
present.
Axial gadolinium-enhancedT1-weighted magnetic
resonance image obtained at the level of the midbrain in
the same patient as in the previous image. A
heterogeneously enhancing mass is seen in the right medial
anterior cerebellum, with mass effect on the right posterior
lateral midbrain and fourth ventricle.The image shows
enlargement of the temporal horns of both lateral
ventricles as a result of obstruction by the cerebellar mass
at the level of the fourth ventricle.
Dr Ahmed Esawy

105. Dr Ahmed Esawy

106. Dr Ahmed Esawy

107. upward herniation from cerebellar infarction /oedema
Dr Ahmed Esawy

108. ascending transtentorial herniation. Axial CT scan obtained after posterior fossa surgery
with subsequent cerebellar hemorrhage and edema. Perimesencephalic cistern is effaced.
Trapped temporal horns are caused by aqueductal compression and hydrocephalus
Dr Ahmed Esawy

109. unilateral ascending transtentorial herniation. A, Axial CT scan of patient with right cere-
bellar astrocytoma shows distortion of right quadrlgeminal cistern (arrow) and brainstem
compression caused by upward herniation. B, AxialTi-weighted MR image shows leftsided
cerebellar cystic medulloblastoma with marked compression and rotation of midbrain.
Frequently, midbrain is elevated and pons, following midbrain, is forced against clivus
Dr Ahmed Esawy

110. Sphenoid/alar
herniation
Transalar Herniation
brain herniates across the greater sphenoid wing (GSW) or "ala"
ascending > descending
Dr Ahmed Esawy

111. descending transalar herniation
Descending transphenoidal herniation occurs when anterior cranial
fossa mass effect causes displacement of the posterior frontal lobe
over the sphenoid wing into the middle cranial fossa.
Ascending transalar herniation
Ascending transphenoidal herniation is produced by middle cranial
fossa mass effect, which causes displacement of the anterior
temporal lobe over the sphenoid ridge into the anterior cranial
fossa.
Dr Ahmed Esawy

112. transalar herniation
Temporal lobe + sylvian fissure + MCA
up and over the greater sphenoid wing
The middle cerebral artery can become compressed
between the displaced brain and the sphenoid ridge,
resulting in middle cerebral artery infarction
Although vascular compromise may occur with
transphenoidal herniation, it is rare. Moreover, the
clinical features of this type of herniation are poorly
defined.
Dr Ahmed Esawy

113. ascending transalar herniation. Axial contrast-enhanced CT scan of patient with right
temporal lobe gliobiastoma shows contrast filled right middle cerebral artery (arrow)
displaced anteriorly.Also present is asymmetry and effacement of ipsilateral sylvian
fissure.These changes indicate ascending transalar herniation.
Dr Ahmed Esawy

114. Dr Ahmed Esawy

115. Dr Ahmed Esawy

116. Dr Ahmed Esawy

117. Transphenoidal herniation. Sagittal enhanced Tl- weighted MR image
demonstrates a large ring enhancing mass (arrowhead) in the right frontal lobe
causing descending transphenoidal herniation (arrow)
Dr Ahmed Esawy

118. Descending transalar herniation. A, Coronal enhancedTi-weighted MR image shows left
frontal lobe glioblastoma.When compared with normal right side, medial orbital gyrus of
left frontal lobe Is displaced over sphenold ridge into middle cranial fossa (arrow). B, Sagittal
enhancedTi-weighted MR image shows tumor and resultant transalar herniation (arrow).
Left syivian fissure is effaced. Compare this image with normal right side. C, Sagittal
enhancedTi-weighted MR image shows normal position of right frontal lobe (asterisk)
above sylvian fissure (arrow
Dr Ahmed Esawy

119. Extracranial herniation
/Transcalvarial /transdural
herniation
Dr Ahmed Esawy

120. Dr Ahmed Esawy

121. Extracranial herniation /Transcalvarial
/transdural/Transcranial herniation
the brain squeezes through a fracture or a surgical site in the skull. Also called
"external herniation
•Traumatic
–infants or young children with a comminuted inward skull fracture
•Iatrogenic
–a burr hole, craniotomy, or craniectomy
MR best depicts these unusual herniations.
•The disrupted dura
–discontinuous black line onT2WI
–Brain tissue, blood vessels, and CSF, are extruded through the defects into the
subgaleal space Dr Ahmed Esawy

122. Nonenhanced computed tomography (CT) scan of the brain at the level of the body of
the lateral ventricles was obtained in a 37-year-old man who underwent a right
frontotemporal decompression craniectomy for a large right frontal hematoma after a
skiing accident. A focal hypoattenuating infarct is seen in the right frontal lobe, with an
adjacent edematous brain parenchyma herniating through the right frontotemporal
craniectomy defect.The patient had communicating hydrocephalus with dilatation of
the lateral ventricles.
Dr Ahmed Esawy

123. Dr Ahmed Esawy

124. fungus cerebri. A, Axial CT scan of patient with chronic head injury shows left hemispheric
encephalomaiacia and dilated lateral ventricle. Brain tis- sue is identified herniating through
calvarlal defect. B, AxialTi-weighted MR image of patient with severe head trauma. Swollen
brain is seen herniating through calvarial defect (arrows outline margins of defect ). Hemorrhage
is seen adjacent to defect’s anterior rim, which may be result of herniatlon or initial injur
Dr Ahmed Esawy

125. focal herniation Into surgical defect. Coronal contrast- enhancedTi-weighted MR
image of patient following radical mastoidectomy for cholesteatoma that extended
into epitympanum and mastoid antrum. Postoperatively, there Is dehiscence of
tegmen tympani with focal herniatlon of temporal lobe into middle ear cavity (arrow)
sur- rounded by enhancing granulation tissue.This finding can easily be misinterpreted
as middle ear mass Dr Ahmed Esawy

126. Dr Ahmed Esawy

127. Dr Ahmed Esawy

128. Common CNS Herniations:
Dr Ahmed Esawy

129. Cerebral Herniation:
PathogenesisSite of
herniation Effect Clinical consequence
Transtentorial Ipsilateral 3rd cranial nerve
compression
Ipsilateral fixed dilated pupil
Ipsilateral 6th cranial nerve
compression
Horizontal diplopia, convergent squint
Posterior cerebral artery
compression
Occipital infarction Cortical blindness
Cerebral peduncle
compression
Upper motor neurone signs
Brainstem compression and
haemorrhage
Decerebrate posture Cardiorespiratory
failure
Death
Foramen
magnum
Brainstem compression and
haemorrhage
Decerebrate posture Cardiorespiratory
failure Death
Acute obstruction of CSF
pathway
Decerebrate posture Cardiorespiratory
failure
DeathDr Ahmed Esawy

130. THANKYOU
Dr Ahmed Esawy

131. Pathogenesis:
 Supratentorial herniation common. 3 sub types
 Subfalcine herniation:The cingulate gyrus of the frontal
lobe (commonest) :The brain can shift across falx cerebri
 Central transtentorial herniation: displacement of the basal
nuclei and cerebral hemispheres downward
 Uncal herniation: Medial edge of the uncus and the
hippocampal gyrus
 infratentorial herniation : Cerebellar (tonsillar)
herniation: - tonsil of the cerebellum is pushed
through the foramen magnum and compresses the
medulla, leading to bradycardia and respiratory
arrest.
Dr Ahmed Esawy

132. Subfalcine Herniation: in brain
trauma.Contusion of the inferior
temporal lobe (blue arrow) has
resulted in diffuse edema.
(compressed and flattened gyri
on the right).
This has resulted in subfalcine
herniation of the cingulate gyrus
(red arrow), with a secondary
hemorrhagic infarction above
that (black arrow). A midline shift
from right to left is also present,
as is uncal herniation (yellow
arrow).
Dr Ahmed Esawy

133. Uncal Herniation:
Inferior view,The
herniated uncus is
bulging over the
position of the
tentorium (black
arrows) and
compressing the
midbrain.The two
mammillary bodies
(blue arrows) have been
shifted to the patients
right due to the
pressure.
Dr Ahmed Esawy

134. Uncal Herniation:
Dr Ahmed Esawy

135. acute brain swelling + Uncal
Herniation Swelling of the left
cerebral hemisphere
has produced a shift
with herniation of
the uncus of the
hippocampus
through the
tentorium, leading
to the groove seen
at the white arrow.
Dr Ahmed Esawy

136. Cerebellar Tonsil -
Herniation Note the cone shape of the
herniated tonsils around the
medulla in this cerebellum
specimen.
 Results in compression and
Duret hemorrhages in the
pons.
Dr Ahmed Esawy

137. Transtentorial herniation:
 Transtentorial herniation
at the base of the brain. A
prominent groove
surrounds the displaced
parahippocampal gyrus
(arrow).The adjacent 3rd
nerve (N) is compressed
and distorted and the
ipsilateral cerebral
peduncle (P) is distorted
with small areas of
haemorrhage.
Dr Ahmed Esawy