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  • Writer's pictureguillermovazquezdc

Blog 5: Back pain resolution and UC Specific: biomechanics and neurology

Updated: May 14, 2021

On my Facebook Live video this week, I described upper cervical subluxations as taking the body hostage. While that may sound like a figurative analogy, it is in fact, very much a literal one. Try as it might, the brain and nervous system cannot cope with the biomechanical, neurologic and physiologic compromise caused by what we refer to as the Upper Cervical Subluxation Complex.

While the contact for the UC Specific adjustment is on the neck, it is not a neck adjustment. It's a full-spine, full-body adjustment that allows the anatomy to return to an ideal adaptation -- not a week or months later -- but, immediately, assuming that it's done correctly, of course. What we see clinically and have reported for decades in our chiropractic research is that this sudden, structural realignment resolves chronic, unrelenting back pain, sometimes gradually over a period of days and weeks but many times all at once, immediately post-first adjustment, never to come back. So how does that happen from a contact on the neck?

To me, this is primarily an issue of biomechanics. As I've written before, the two upper cervical vertebrae are a marvel of evolutionary engineering. However, not even thousands of years of evolution have completely solved the riddle of how to place a 14-pound bowling ball on top of a two ounce bone because the flexibility allowed by the upper cervical spine unfortunately comes at the expense of stability. And because those two bones are only held together by muscles and ligaments and not by discs and interlocking joints as the rest of the vertebrae below, they are the only two vertebrae that can actually create pressure on the spinal cord when misaligned -- short of deposition of bone into the canal -- and where we can have true torqued subluxations along all three axes. Although not impossible, torqued subluxations like this are very rare below the upper cervical spine. When these two bones gets locked under the occiput, they are locked and the body has no real recourse to address this very critical problem.

One result of this neuropathophysiology, and the main mechanism at play in back pain, is the muscular maladaptation that occurs. In order to keep itself level when there's an upper cervical problem, the brain engages its own righting reflex called the labyrinthine reflex. In a chain reaction down the body, this causes one shoulder to go high, the opposite hip to go high and the ipsilateral leg to go short. Muscles up and down the back and down the limbs become tight and contracted and enter abnormal compensatory patterns. Being in such a maladaptive state structurally may be tolerable for a few months but long-term this is not tenable. But it's for this reason that patients can undergo as many modalities, therapies and surgeries as they want for their back ailments without any meaningful results. Because biomechanically, the problem remains -- it's at the top of the spine and no one's going to tell them about it.

The neurologic aspect is of course paramount as well, although in the case of back pain I think it plays I more passive role as it's being acted upon by a biomechanical problem. However, the central nervous system sends and receives information from the muscles and joints through the tracts of the spinal cord. The dorsal and lateral tracts of the cord send afferent sensory information, including pain, temperature, vibration, touch and proprioception signals from the body, including the muscles and joints, up the spinal cord. The brain then assimilates this input along with that coming from the eyes and ears to help position the body in space and sends efferent motor input down the cord into the muscles to coordinate movement. Of critical importance here are the extra-pyramidal tracts, such as the reticulospinal tracts, that control involuntary postural muscle tone as these are the tracts that effectively balance and relax muscle tone down the back once the upper cervical compromise is removed and the labyrinthine and other tonic postural reflexes can fire and engage properly to relax and rebalance the musculature.

However, in the presence of an upper cervical subluxation, the nature of the information sent up the tracts by the tonic and contracted muscles and joints changes. Nociceptive, or pain input, increases and mechanoreceptive, or balance input, decreases. As a result the information then coming down the motor tracts from the brain may also be impaired. But even if it's not, the biomechanical compromise created by the Upper Cervical Subluxation Complex prevents neuropathways from executing the efferent information. In chiropractic, this is called dysafferentiation and is exemplary of a safety-pin cycle unclasped.

More recently, research into several nuclei found in the upper spinal cord and lower brainstem have helped us understand the complex anatomy and functional role of this area. Many of the ascending and descending tracts of the spinal cord decussate, or cross to the opposite side of the cord, in this area as they head either up into the brain or down to synapse with lower motor neurons. The central cervical nucleus, external cuneate nucleus and nucleus tractus solitarius, form synapses that regulate muscle tone, balance and visceral organ function, respectively. Of course, of importance in this entry is the first of these. The central cervical nucleus is a long, meandering, sometimes ill-defined structure running from the levels of the fourth to first cervical vertebrae. A landmark study in the Journal of Neuroscience from 2007 described its role as follows:

The CCN projection is generally considered to underlie spinal somatic reflex circuits, such as those for the tonic neck reflex involved in postural control.

As UC Specific practitioners we've long understood that this area of the body is the seat of autonomic function in the body and as such regulates muscle tone. Clinically, this is confirmed every day.

While the neurologic pathways involved in these processes are no doubt as varied and complex as the conditions and diagnoses they create, as a chiropractor, I assert that the solution to many of these problems is not. The body needs no help. It just needs no interference.

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