Inflammation can decrease blood flow. It may increase blood flow to the local tissue that is inflamed but the addition pressure can reduce blood that needs to flow through the area. Look up compartment syndrome and see the damage inflammation can do. It is valuable to reduce inflammation so it does not reduce blood flow.

A chiro adjustment can cause an inflammatory response because of the movement of the atlas, etc. There is no positive value to that inflammatory response. Reducing it or preventing it can allow the atlas to settle into place.

In this instance, the additional pressure inflammation can reduce vascular blood flow to the brain stem and restrict proper nerve fiber signal transmission reducing its effective function.

This is why it is important to check foot or hand nerve sensation when there is inflammation higher up the extremity.

Regarding chiros being quacks or such. There is a broad spectrum of chiros and their skill sets. Some may provide limited benefit. Others can provide very important benefit. I've been treated by over 18 different chiros over 35 years. Only 4 provided substantial benefit. 4 provided some limited benefit and the rest were just going through the motions. It is up to the patient to decide to continue or move on to a different chiro or treatment protocol.

blessed's point is to verify her experience with outside perspective.