Blood Flow In The Upper Cervical Spine
Blood is an essential component of animal life. It is the blood that carries the life-sustaining nutrients including oxygen to every organ, tissue and cell in the body. Arteries and veins are like rivers and streams that wander through the body, each has it’s own determined route through or around structures with many branches and tributaries that are delivering goods along the way.
Arteries are round tube like structures that are encased in strong muscle giving them a rigid and solid composition. A vein, on the other hand, lacks the thick muscle casing and is more like a deflated balloon, very pliable and flaccid. The difference between the two are important to understand not only for the purpose of physiology, but also for the structural integrity. These structures are susceptible to the anatomy around them. While arteries are more rigid and less likely to get compressed and deform, veins are easily compressed by the solid structures such as bones. This may, in certain circumstances, compromise blood flow.
Arteries are typically deep structures, pumping the oxygen rich blood to tissue. Veins are commonly found more superficial. They carry the deoxygenated blood that is a blueish hue and can usually be seen on the back of the hands and feet. In fact, if you have prominent veins on the back of your hand, you can experiment how easy it is to compress and interfere with the blood flow by pressing directly on it.
When an artery is blocked, it is a serious event that demands immediate attention. When a vein is blocked, there may not be any indication that there is a problem. A constant “stasis” of blood creates a dangerous situation as it prevents fresh blood from delivering nutrients to the body. It is like an accident on the highway that slows the flow of traffic.
The internal jugular veins (right and left) are the largest veins in the cranial region. These are what drains the majority of the blood from the cranial vault and allow for fresh blood to circulate. In normal anatomy, the proximity of the internal jugular veins and the atlas (the first vertebra in the neck) create a precarious situation. If the atlas rotates a significant degree or slips forward, it may compress one of the internal jugular veins, obstructing the flow of blood out of the cranium. The many other veins in the head and neck may be able to handle an increased rush of blood, but decreased blood flow will compromise the efficiency of the body systems in general.
This very situation is becoming more of an interest as researchers look at possible contributors to neurodegenerative diseases like: Multiple Sclerosis, Parkinson's Disease, and Alzheimer's Disease. It is being looked at by neurologists, vascular surgeons and a specialty in chiropractic called upper cervical chiropractic.
This angiogram shows a “bow-tie” appearance where the vertebral artery wraps around the atlas before ascending to the cranium. It is easy to see how a chronic mal-positioning of this vertebra would cause disturbance in blood flow.
