Posterior fossa venous anatomy SupracerebellarInfratentorial Surgical Approach

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Posterior fossa venous anatomySupracerebellar/In
fratentorial Surgical Approach

• Hamid Aliabadi, MD
• Duke University

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Posterior fossa venous system 4 major groups

• superficial veins-cortical surface drainage
• Tentorial surface drained by superior hemispheric
  and superior vermian veins
• Suboccipital surface drained by inferior
  hemispheric and inferior vermian veins
• Petrosal surface drained by the anterior
  interhemispheric veins
• deep veins
• Veins of the cerebello-mesencephalic,
  cerebello-medullary and cerebello-pontine
  fissures
• Veins of the sup, mid, and inf cerebellar
  peduncles
• brainstem veins
• bridging veins
• Collect into 3 groups Galenic group draining
  into the v of Galen, Petrosal group draining into
  the petrosal sinuses, and a Tentorial group that
  drains into the tentorial sinuses, which drain
  into the transverse, straight or superior
  petrosal sinuses.

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• Tentorial surface of the cerebellum is drained by
  the superior hemispheric and superior vermian
  veins
• Anterior group into the Galenic vv
• Posterior group into the major tentorial sinuses
• Straight, transverse and sup petrosal vv

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• Suboccipital surface of the cerebellum is drained
  by the inferior hemispheric and inferior vermian
  veins
• Empty into the major tentorial sinuses

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• Petrosal and anterior brainstem surfaces are
  drained by the anterior hemispheric veins
• Empty into the superior petrosal sinus via the
  superior petrosal veins

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Key points

• Tentorial sinuses receive venous outflow from
  both the cerebrum and the cerebellum
• Veins from the posterior fossa pass toward, but
  often medially or deep to the transverse sinuses
• Venous blood drains into the tentorial sinuses
  that empty into the transverse sinus afterwards.
• Mastoidectomy exposure allows visualization of
  the sigmoid sinus and jugular bulb.

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Suboccipital surface of cerebellum and
cerebellomedullary fissure. Veins near area of
Chiari surgery drain into the Inferior Vermian
vein and they ascend into the tentorial sinuses.
Retracting tonsils allows you to see the
Cerebellomedullary veins that cross the inferior
medullary velum at the cerebellomedullary fissure.
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Arterial blood supply posterior fossa

• SCA
• Superior half of the cerebellum and parts of the
  midbrain and pons
• AICA
• Caudal pons
• Flocculus and anterior-inferior part of
  cerebellum
• PICA
• Choroid plexus of the fourth ventricle
• Inferior surface of cerebellum
• Lateral medulla

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