Lately I have been having writers block with all the beautiful weather. Thanks to a friend of mine Ron for posting this link about Medtronic shunts. It has great information you can find if you follow the Medtronic link.
If you want to find Ron on facebook you can friend him here Patrick Kelleher . Just tell him you are coming from Pepper Knows Best or Monica sent you.
This site shows how the shunt works. How it is programmed and many things you need to know about your shunt that many don't know.
Even if you don't have a Medtronic this will help you understand how your codmen works in a since also.