Identification of a novel path for cerebrospinal fluid (CSF) drainage of the human brain

Abstract

ABSTRACTHow cerebrospinal fluid (CSF) drains from the human brain is of paramount importance to cerebral health and physiology. Obstructed CSF drainage may result in increased intracranial pressure and a predictable cascade of events including an enlarged subarachnoid space, dilated cerebral ventricles and ultimately cell death. The current and accepted model of CSF drainage in humans suggests CSF drains from the subarachnoid space into the sagittal sinus vein. Here we identify a new structure in the sagittal sinus of the human brain by anatomic cadaver dissection. TheCSF canalicular systemis the terminal CSF drainage of the human brain. It consists of paired channels on either side of the sagittal sinus vein that communicate directly with subarachnoid cerebrospinal fluid via virchow robin (perivascular) spaces. Fluorescent injection confirms that these channels are patent and that flow is independent of the venous system. Computer assisted tomography identified flow from the sagittal sinus to the cranial base. We verify our previous identification of CSF channels in the neck that travel from the cranial base to the subclavian vein. This information suggests a novel path for CSF drainage of the human brain and nerves that may represent the primary route for CSF recirculation. These findings have implications for basic anatomy, surgery, and neuroscience, and highlight the continued importance of gross anatomy to medical research and discovery.