Editing Human brain (section)

====Blood drainage====
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[[Cerebral veins]] drain [[Blood#Oxygen transport|deoxygenated blood]] from the brain. The brain has two main networks of [[vein]]s: an exterior or [[Superior cerebral veins|superficial network]], on the surface of the cerebrum that has three branches, and an [[Internal cerebral veins|interior network]]. These two networks communicate via [[anastomosis|anastomosing]] (joining) veins.{{sfn|Gray's Anatomy|2008|pp=254-6}} The veins of the brain drain into larger cavities of the [[dural venous sinuses]] usually situated between the dura mater and the covering of the skull.{{sfn|Elsevier's|2007|pp=311–4}} Blood from the cerebellum and midbrain drains into the [[great cerebral vein]]. Blood from the medulla and pons of the brainstem have a variable pattern of drainage, either into the [[spinal veins]] or into adjacent cerebral veins.{{sfn|Gray's Anatomy|2008|pp=254-6}}

The blood in the [[Anatomical terms of location#deep|deep]] part of the brain drains, through a [[venous plexus]] into the [[cavernous sinus]] at the front, and the [[superior petrosal sinus|superior]] and [[inferior petrosal sinus]]es at the sides, and the [[inferior sagittal sinus]] at the back.{{sfn|Elsevier's|2007|pp=311–4}} Blood drains from the outer brain into the large [[superior sagittal sinus]], which rests in the midline on top of the brain. Blood from here joins with blood from the [[straight sinus]] at the [[confluence of sinuses]].{{sfn|Elsevier's|2007|pp=311–4}}

Blood from here drains into the left and right [[transverse sinus]]es.{{sfn|Elsevier's|2007|pp=311–4}} These then drain into the [[sigmoid sinus]]es, which receive blood from the cavernous sinus and superior and inferior petrosal sinuses. The sigmoid drains into the large [[internal jugular vein]]s.{{sfn|Elsevier's|2007|pp=311–4}}{{sfn|Gray's Anatomy|2008|pp=254-6}}