Cervical Lordosis, The Cervical Curve

Fall has descended upon us, and football season is in full swing. Every time I watch a football game I marvel at how these athletes can take such a beating and continue to get up, especially when the amount of whiplash is so evident. A couple of weeks ago one theme seemed to be common across several injuries spanning many different NFL games. A defensive player would attempt to tackle the ball carrier and do so with his head tucked, ultimately causing extreme flexion (chin to chest) and in few cases a severely sprained neck. Anyone who has been in a car accident knows the feeling. Lingering soreness followed by extreme muscle fatigue, pain on motion of the neck and the feeling as though all of the muscles in front of the neck are on lockdown, but what exactly happens to your neck because of these events?

Every day in my office I deal with the loss of the proper frontwards curve in the neck (the cervical lordosis). It is exceedingly common. In extreme cases, the curve can actually be reversed (a kyphosis), whereas the front of the spine is the concave side. Then it dawned on me, I help correct these misalignments daily, but how often am I teaching the importance of the proper curve in the first place? How it develops? Or how it is lost? Am I getting the message out to those in need? Please share this newsletter with your family and friends.

The normal cervical lordosis is the natural inward curve of the neck when viewed from the side so that the convexity is on the front and the concavity is on the back. This curve begins to form as early as 10 weeks of fetal development[i] and is cemented during infancy and adolescence. Tummy time is very important for babies as it encourages a proper curve by the child holding their head in extension. Loss of lordosis can begin early in childhood with injuries from falls and continues into adulthood with sports injuries, stress, and whiplash.[ii] Unfortunately, many or our “normal” daily activities can also decrease the cervical lordosis, such as viewing low lying computer screens (below eye level), sleeping with two pillows, or even sitting in a recliner.

Many studies are showing a clear causal relationship between loss of lordosis and neck complaints, including neck pain and stiffness, headaches, premature degeneration, disc herniation, and numbness/tingling or weakness in the arms. A study from 1974 showed that a sharp reversal of the curve would result in degenerative changes in 60% of patients.[iii] Literally, a reversed curve causes arthritis in the neck. A study from 2005 in the Journal of Manipulative and Physiologic Therapeutics found:
“The odds that a patient with cervical pain had a lordosis of 0 degrees or less was 18 times greater than for a patient with a non-cervical complaint. Patients with cervical pain had less lordosis and this was consistent over all age ranges.”[iv] The authors of the study went so far as to recommend “Maintenance of a lordosis […] could be a clinical goal for chiropractic treatment.”

But why neck pain? What does loss of the curve actually do to cause pain? Tingling? Numbness? Headaches? It’s actually very simple. A lack of cervical lordosis places weight bearing stress onto joints in the neck where they would normally not directly bear weight. This causes inflammation, stiffness, and resultant muscle spasm to stabilize the area. Muscles in the upper part of the neck then irritate nerves that travel up and over your head into the scalp producing tension headaches. As time progresses, supporting ligaments in the back of the neck stretch and those in the front contract, working to further stabilize the neck in this unnatural posture. Weight is born mainly on the lower segments of the neck (C5-7), which then typically degenerate first. Arthritic spurring progresses in these dysfunctional segments, which can then impinge the exiting nerve roots and cause symptoms in the arms and hands such as tingling, numbness, electric shocks, and weakness. I have seen many a failed carpal tunnel surgery due to the nerve being irritated in the neck and elbow, not just at the wrist.

As the curve becomes kyphotic, other neurologic complaints can manifest. The spinal cord is tethered at the top by its attachment to the brain, and at the bottom by the lumbar nerve roots and meningeal attachment to your tailbone. When the normal, relaxed neck curve is reversed, the spinal cord is tractioned and forced against the back of the bodies of the vertebrae in the neck. This can cause sensory issues anywhere in the body as the pathways for sensation are located in the back of the cord, and thus are affected first by long-term traction. The motor pathways are in the front of the cord and are compressed rather than stretched. Compression of a nerve is never a good thing, especially when it’s the spinal cord itself.

What many people do not know is that most nerve fibers are insulated by a fatty layer called “myelin.” This layer works to allow the signal the nerve generates to travel at significantly faster speeds than it could otherwise. Chronic compression of a nerve can lead to the death of the cells that maintain this layer; causing the signal the nerve carries to be forever slower and thus not produce its intended effect. An animal study from 2005 sought to reproduce demyelination (a common diagnostic criteria for Multiple Sclerosis) via cervical kyphosis in Japanese small game fowls. The results of that study were startling. The authors concluded:

“Progressive kyphosis of the cervical spine resulted in demyelination of nerve fibers in the funiculi and neuronal loss in the anterior horn due to chronic compression of the spinal cord. These histologic changes seem to be associated with both continuous mechanical compression and vascular changes in the spinal cord.”[v]

In short, the reversed curve caused changes in the spinal cord indicative of progressive neurologic conditions. The cervical kyphosis was obtained using surgical means, but like any symptom of a cause, there are levels of dysfunction. The methods used in this trial prevent duplication in humans due to obvious ethical implications, but the mechanical methods would hold true. It is a fascinating area of research and one I hope continues to grow. To reiterate, the researchers showed that a cervical kyphosis (loss of cervical curve) causes changes in the spinal cord that lead to progressive neurologic degeneration. As Chiropractors, we have argued this for generations.

Chiropractic focuses on alignment of the spine so that the nervous system can function optimally. Clearly, research is showing that a lack of sufficient cervical lordosis is a factor in a wide range of conditions, some of which are severe.

If you are experiencing any of these symptoms—headache, stiff neck, neck pain, numbness, tingling, or weakness of your hands, or you would just like to get yourself or your family checked, feel free to contact my office and correct the cause.

Be well, and have an exceptional day!

Daniel J. Myerowitz D.C., Dipl. Ac. (AACA)
Myerowitz Chiropractic & Acupuncture Clinic
291 Main Road
Holden ME 04429
989-0000

[i] Bagnall KM, et al. A radiographic study of the human fetal spine. I. The development of the
secondary cervical curvature. J Anat 1977; 123: 777-82.

[ii] Harrison et al. Comparison of axial and flexural stresses in lordosis and three buckled
configurations of the cervical spine. Clinical Biomechanics 2001; 16 (4): 267-84.

[iii] M. Hohl, Soft Tissue Injuries of the Neck in Automobile Accidents, Journal of Bone & Joint Surgery, Vol 56a, No. 8: 1675 – 1681 (December 1974).

[iv] McAviney J, Schulz D, Bock R, Harrison DE, Holland B. Determining the relationship between cervical lordosis and neck complaints. Journal of Manipulative & Physiological Therapeutics. 2005 Mar-Apr;28(3):187-93.
[v] Shimizu, Kentaro MD; Nakamura, Masaya MD; Nishikawa, Yuji MD; Hijikata, Sadahisa MD; Chiba, Kazuhiro MD; Toyama, Yoshiaki MD. Spinal Kyphosis Causes Demyelination and Neuronal Loss in the Spinal Cord: A New Model of Kyphotic Deformity Using Juvenile Japanese Small Game Fowls. Spine: 1 November 2005 – Volume 30 – Issue 21 – pp 2388-2392 http://journals.lww.com/spinejournal/Abstract/2005/11010/Spinal_Kyphosis_Causes_Demyelination_and_Neuronal.8.aspx

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