The third ventricle makes a bit more cerebrospinal fluid and then sends all of it to the fourth ventricle via the cerebral aqueduct.
第三脑室也产生一些脑脊液,然后把全部的脑脊液通过大脑(脑室系统)导水管排入第四脑室。
英语百科
Cerebral aqueduct
The cerebral aqueduct, also known as the aqueductus mesencephali, mesencephalic duct, or the aqueduct of Sylvius is within the mesencephalon (or midbrain), contains cerebrospinal fluid (CSF), and connects the third ventricle in the diencephalon to the fourth ventricle within the region of the mesencephalon and metencephalon, located dorsal to the pons and ventral to the cerebellum.