ProAgonist--
You need to look at the anatomy of the back of the neck....Google it. There are two major arteries going up in a narrow space in your back neck to bring blood to the base of the brain. They are called vertebral arteries. They can get compressed (or damaged) and cause major grief like stroke, etc.
There is a condition called beauty salon stroke, where when patrons (mostly women) sit with their heads back...actually have strokes!
http://www.ncbi.nlm.nih.gov/pubmed/12023594
Also irresponsible chiropractor adjustments of the neck can cause strokes too.
So you will want to avoid extreme backwards extension to your neck, or blows from behind.
__________________
All truths are easy to understand once they are discovered; the point is to discover them.-- Galileo Galilei
************************************
.
Weezie looking at petunias 8.25.2017
****************************
These forums are for mutual support and information sharing only. The forums are not a substitute for medical advice, diagnosis or treatment provided by a qualified health care provider. Always consult your doctor before trying anything you read here.