EJC wrote:So the emissary veins have over developed to compensate in some way for the blockage in the jugulars but these veins still don't have enough capacity to compensate completely?
So that is the reflux and a symptom of that is headaches?
It's believed that the only time when the emissary veins can grow in size is prenatally, because they actually travel through channels through the skull itself. The emissary veins are present prenatally and the skull forms around them at some point during development. This is fascinating, in my opinion, and it supports the notion that CCSVI blockages can be congenital in origin, if the overdevelopment of the emissary veins is a compensation for the blockage in the IJVs that is present prenatally. I think you are correct that even if the emissary veins overdevelop, they do not get as big as an internal jugular vein itself, so it does not solve the problem but at least gets some of the flow out of the cranium.
The reflux is the flow taking alternate routes because the outflow through internal jugular veins is obstructed. The headache is a symptom of venous congestion in the emissary veins and/or neck muscle veins that are one of those alternate routes.
This is all my best understanding as a layman. Ok, I can see where this is complicated, especially because not all of this is laid out in every post, but was at some point in the last two years. Dr. Schelling had thoughts about the emissary veins being integral to the development of brain lesions, because if we have these larger emissary veins leading out, the flow can reverse under pressure such as coughing, and the emissary vein turns into an inward route rather than an outward route, I think? I do not have a full grasp of Dr. Schelling's ideas.