Blood supply of the spine.”Old faithful” and “Glymphatic”

I discovered recently, that once you start suggesting that stretching your back  isn’t a good idea (at all)  the yoga  and pilates lobby comes out. So you engage with them. You point them to research, they  come back with belief, you point out that stretching  the back only deadens the nerve endings, you supply references, they supply none.

Eventually, though, even they get a bit  worried by their lack of causality  and science.  What does stretching do, they ask themselves. They come back with, what  I call, “the old faithful Argument”

The Old faithful argument runs like this. You need to move your back, and stretch it,  to pump the blood in an out.

To begin to understand “bad backs” we need to understand the vascular and neuro anatomy of the spine. I am no expert on this, but here is my 1st attempt at some cut and pasting to inform my future thinking

This following link goes into worrying detail about the blood supply of the spine.  My take home message , I think , is this. The spine is amazingly well supplied with blood. Things may go wrong,  but in  most cases, if you need to move the spine to pump blood in and out,  you have very , very severe problems.Nothing to do with normal back pain.

The veins in the back are quiet amazing too

“In 2011, researchers from the Department of Neurological Surgery at Ohio State Medical Center summarized the significance and current understanding of several aspects of the CSVS in their review article: “Today, the vertebral venous plexus is considered part of the cerebrospinal venous system, which is regarded as a unique, large-capacitance, valveless plexiform venous network in which flow is bidirectional that plays an important role in the regulation of intracranial pressure with changes in posture and in venous outflow from the brain, whereas in disease states, it provides a potential route for the spread of tumor, infection, or emboli.”

Maybe we need to pump the spinal lymphatic system?

“the lymphatic system does not extend into the brain or spinal cord, despite the high metabolic activity of neural tissue and its high sensitivity to changes in the extracellular environment, including the build-up of metabolic waste products. Such an absence of lymphatic vessels has led scientists to believe that an alternative process exists, which takes the place of this critical lymphatic function” ( well according to Wikipedia)

In the same review, it suggests this

“In 2012, it was shown that AQP4 is essential for paravascular CSF–ISF exchange. Analysis of genetically modified mice that lacked the AQP4 gene revealed that the bulk flow-dependent clearance of interstitial solutes decreases by 70% in the absence of AQP4. Based upon this role of AQP4-dependent glial water transport in the process of paravascular interstitial solute clearance, Iliff and Nedergaard termed this brain-wide glio-vascular pathway the ‘glymphatic system’.”

Sooo, we need to get a handle on what the hell the “glymphatic system” is! maybe this helps. As the PR says, “It’s as if Dr. Nedergaard and her colleagues have uncovered a network of hidden caves and these exciting results highlight the potential importance of the network in normal brain function,” said Roderick Corriveau, Ph.D., a program director at NINDS.

Take home message: get more sleep. Stretching a bit to pump blood in and out of your spine is probably incorrect

The relationship of lumbar flexion to disability in patients with low back pain

The relationship of lumbar flexion to disability in patients with low back pain,  by M Scott Sullivan Lisa Donegan Shoaf and Daniel L Riddle (Physical Therapy March 2000 vol. 80 no. 3 240-250)

is an interesting study


Patients completed the Roland-Morris Back Pain Questionnaire (RMQ), and the therapists assessed lumbar spine flexion AROM (active range of motion) using a dual-inclinometer technique at the initial visit and again at discharge.


Measures of lumbar flexion AROM should not be used as surrogate measures of disability. Lumbar spine flexion AROM and disability are weakly correlated, suggesting that flexion AROM measures should not be used as treatment goals.

Free full study here. it “sort of” breaks the link between spine mobility and future back trouble.

The study also draws some very interesting observations about therapist biases

As always,  this gives us another crop of references to follow up

6 muscles of the back are functionally different from limb muscles

Limb muscles create movement, torso muscles create stability.

The simple act of walking requires spine stability. There are no agonists and antagonists in the torso they are all required to stabilise force generated elsewhere in the body.

If your therapist treats your core muscles in the same way as limb muscles, they are simply going to extend the pain in your back

Elite performers generate force in their hips, and it is transmitted through a stiffened core.

Spinal Control: The Rehabilitation of Back Pain: State of the art and science
edited by Paul W. Hodges, Jacek Cholewicki, Jaap H van Diee

Do you slump?

I fix the backs of sedentary people and of several elite athletes, also middle range  Crossfit athletes.

One thing Ive notice about those with bad backs is their ability to push themselves beyond the call of duty.  In fact they have the reputation of being hard workers, motivated and always on the go!

The reality is , once the doors are closed, they  can head for the settee and slump. For hours!!!! They can happily stay in bed if allowed, and they can be very , very lazy.

Hard ( some would say obsessive) work can sometimes be matched by back destroying  activity elsewhere.

The twist. Is it deadly.

Several researchers have suggested that  twisting of the trunk is associated  with low back pain. the 1st issue we need to deal with is to distinguish  the idea of twisting  from generating twisting torque.

Torque  in the torso can be achieved  whether or not the spine itself is twisted.

In general moderate twisting isn’t dangerous. over the years the debates have included  twisting quickly and breaking the speed by hitting the end range of motion,  back in 1970, Farfan  suggested disc twisting  could damage  the collagen fibres  in the annulus, especially if a neutral arch had been lost.  Other reports say that twisting is less dangerous as the facet forms a mechanical stop , thus its the facets that can get injured.

What is  Twisting torque? Imagine a twist that applies or transmits force!.As no muscle  is designed (as a primary function),  to create twisting torque all muscles are  contracted, this increases compressive load. 50nm of extension, creates 800 newtons of spinal compression.

Generating high torque, when the  spine is twisted  is problematic. In short are you twisting… well, Ok!  or are you twisting through your spine to load up an axe swing … probably not so good!

Ill show you in a future “Note” how to generate force through your hips and not through your back. But for now, repeated spine flexion will, according to Aultman et al ( 2005), will lead to discogenic trouble.