This animation shows how the csf flows. Most of the csf is produced in the body of the lateral ventricle. Normally, it will flow from the lateral ventricle down through the foramen of Monroe into the III ventricle. From there it proceeds down the aqueduct into the IV ventricle. There are three openings in the IV ventricle: laterally are the foramen of lushka and medially or in the middle is the foramen of magendie. Place your mouse arrow over the picture on the left and click the left arrow to start the animation.
Aqueductal Stenosis is seen in infants and young adults. mostly. It can present later on in the teenage years as well. With more and more people having CT and MRI brain scans, we are seeing people in their 50's and even 70's with aqueductal stenosis. Essentially, the aqueduct is atretic or sometimes the channel will fork into a blind pouch. Since cerebral spinal fluid (CSF) cannot flow down into the IV Ventricle, obstructive hydrocephalus develops. Characteristically, everything proximal to the aqueduct dilates. The IV Ventricle remains normal in size.