Malden wrote: Sry... Back presure? What do you mean with that?
M.
No problem. Certainly not back ache. I was using a fluid dynamics concept.
The easiest way that I can think of to explain it is to think of a syringe without a needle on it compared to one with. The increased resistance that you feel on your thumb whilst pushing the plunger down with the one with a needle – that’s back pressure.
To assist, here are a few definitions of “back pressure” pulled from the internet - one from the engineering field and the other medical:
Pressure developed in opposition to the flow of liquid or gas in a pipe, duct, conduit, etc.; due to friction, gravity, or some other restriction to flow of the conveyed fluid.
Pressure exerted upstream in the circulation as a result of obstruction to forward flow, as when congestion in the pulmonary circulation results from failure of the left ventricle.
Getting back to the jugulars, I consider these to be the exhaust pipes of the brain, and the arteries its fuel supply. Seen thusly, an obstruction in the jugulars should cause an inefficient fuel “burn” in the brain or reduction in volumetric efficiency considering how back pressure should affect such a system.
The arteries are not connected to the veins. That’s why arterial pressure would not necessarily go up due to narrowing of the jugulars. You would expect pooling though and increased pressure in the small blood vessels as described in the CCSVI model.
Note as well that flow will find the path of least resistance and the venous system in the brain does have redundancy built into it. But you would be putting increased load on these other pathways. Further, the back pressure does not have to be dramatic, just chronic such that, over time and with aging, it causes damage.
That's why I think that back pressure is a more accurate term to use than reflux as I would think that to actually see venous flow reverse direction would be a rare event.