I went to my nerosurgeon for a check up on my vp shunt and he felt the valve on my head are they supposed to do that and why?

Yes: Shunts are provided with a one way valve that is designed to open as needed to allow fluid excess to be redirected into the shunt distribution field rather than allow a build up of pressure.Pressing the shunt bubble allows the examiner to know if the valve is working.

VP shunt: Your shunt valve is a reservoir of fluid and some surgeons like to press on it and see how it refills. If there is concern over a shunt failure this test can sometimes be helpful in determining if the shunt is working but not always reliable.