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Thursday, October 09, 2008

Which of the following is not a tributary of Cavernous sinus

Question 8
Which of the following is not a tributary of Cavernous sinus
a.       Superficial middle cerebral vein
b.      Deep middle cerebral vein
c.       Superior petrosal sinus
d.      Inferior petrosal sinus
e.       Not a tributary of Cavernous sinus
Gray 38th Edition Pages 1585, 1587
Ä     Tributaries of Cavernous Sinus
o       Superior ophthalmic vein,
o       A branch from the inferior ophthalmic vein (or the whole vessel),
o       Superficial middle cerebral vein,
o       Inferior cerebral veins
o       Sphenoparietal sinus;
o       Central retinal vein
o       Frontal tributary of the middle meningeal sometimes drain to it.
Ä     The sinus drains
o       to the transverse sinus via the superior petrosal sinus,
o       to the internal jugular via the inferior petrosal sinus and a plexus of veins on the internal carotid,
o       to the pterygoid plexus by veins traversing the emissary sphenoidal foramen, foramen ovale and foramen lacerum and
o       to the facial vein via the superior ophthalmic.
Ä     The two sinuses are connected by anterior and posterior intercavernous sinuses and the basilar plexus. All connections are valveless; the direction of flow in them is reversible.
Ä     If the question had been “Which is a tributary” then the answer is superficial middle cerebral vein
Ä     If the question had been “Which is not a connection” the answer is Deep Middle Cerebral Vein
Inferior Petrosal Sinuses drain the cavernous sinuses to the internal jugular veins. Each begins postero-inferiorly at its cavernous sinus and runs back in a groove between the petrous temporal and basilar occipital bones. Traversing the anterior part of the jugular foramen it ends in the superior jugular bulb. It receives labyrinthine veins via the cochlear canaliculus and the vestibular aqueduct and tributaries from the medulla oblongata, pons and inferior cerebellar surface. According to Browder and Kaplan the sinus is more often a plexus and sometimes drains by a vein in the hypoglossal canal to the suboccipital vertebral plexus.
Propulsion of blood in the sinus is partly due to pulsation of the internal carotid artery. It is also influenced by gravity and hence by the position of the head.

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