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The Chiropractic Impact Report

Courtesy Of Dr. John Doe

October 2016

The Problems with
Loss of Cervical Lordosis

Biomechanics

Biological systems adapt to prolonged mechanical loads. This premise is called viscoelastic creep (1).

vaso-electric creep chart

Orthodontists use the principle of viscoelastic creep when straightening teeth. The braces put a prolonged mechanical load on the teeth in the desired direction and the bone adapts; the alignment of the teeth in the bone changes.

In a similar manner, soft tissues (ligaments, cartilage, tendons, muscles, etc.) also undergo viscoelastic creep when prolonged loads are applied; they mechanically distort and eventually adapt to the applied loads. The classic modern example is the forward head posture and loss of cervical lordosis while viewing or working on hand-held cellular devices (2).

60 degree head bend can place 60 lbs of weight on cervical spine

The inevitable consequence of these prolonged abnormal postures is loss of cervical lordosis. Other causes of viscoelastic elastic loss of cervical lordosis include ergonomics and poor postural habits.

••••••••••

When the spine is viewed from the front or back, it is supposed to be straight. When the spine is viewed from the side, it is suppose to have three curves (3):

  • Cervical Lordosis
  • Thoracic Kyphosis
  • Lumbar Lordosis


Below is the view of the cervical lordosis. Complete reversal of cervical lordosis is cervical kyphosis. Lordosis values are measured using the standard posterior tangent method:

cervical lordosis vs kyphosis

The lateral spinal curves are necessary for proper biomechanical function. The three curves strengthen the spinal column, allowing people to stand up strong in a gravity environment, yet also allowing for greater spinal ranges of motion (3).

••••••••••

Another notorious cause of hypolordosis is trauma. The trauma best documented to cause loss of cervical lordosis is motor vehicle collisions. This is well documented by whiplash-injury pioneer Ruth Jackson, MD, from Baylor Medical School in her 1978 book (4), The Cervical Syndrome.

In 2002, Vincenzo Giuliano, MD, and colleagues, published a study in the journal Emergency Radiology (5). Using MRI, the authors carefully evaluated the cervical spines of 100 whiplash trauma patients and compared them to 100 asymptomatic control subjects.

Loss of normal cervical lordosis (hypolordosis) was observed in 4% (4 of 100) of the normal control subjects. In the subacute post-traumatic subjects, hypolordosis was observed in 98% (98 of 100) of the injured subjects.

••••••••••

Loss of cervical lordosis is associated with a number of problems and clinical syndromes, including those noted below:

Unbalancing the First Class Lever of Upright Posture

Upright posture is a 1st class lever mechanical system:

The fulcrum of a first class lever is the place where the forces are the greatest

The fulcrum of a first class lever is the place where the forces are the greatest. The forces experienced at the fulcrum of a first class lever system are dependent upon three factors:

  • The magnitude of the load (weight)
  • The distance the load is away from the fulcrum (lever arm)
  • The addition of the counterbalancing effort required to remain balanced

If the load was 10 lbs., and the distance from the fulcrum was 10 inches (the lever arm), the force on the fulcrum would be 100 lbs. (10 X 10). In order to remain balanced, the effort on the opposite side of the fulcrum would have to also be 100 lbs. The effective load applied to the fulcrum would be 200 lbs. Thus an actual load of 10 lbs. would have an effective load on the fulcrum of 200 lbs.

If the load was 10 lbs., and the distance from the fulcrum was 10 inches (the lever arm), the force on the fulcrum would be 100 lbs. (10 X 10). In order to remain balanced, the effort on the opposite side of the fulcrum would have to also be 100 lbs. The effective load applied to the fulcrum would be 200 lbs. Thus an actual load of 10 lbs. would have an effective load on the fulcrum of 200 lbs.

In the spine, the fulcrum of the first class lever of upright posture is primarily the vertebral body/disc, and the two facet joints. Pertaining to the head/neck complex, the load is the weight of the head multiplied by the distance between the center of mass of the head and the fulcrum. The effort is the amount of force generated by the contracting muscles on the opposite side of the fulcrum to keep the lever from falling over. This constant muscle contraction with more effort creates muscle fatigue and myofascial pain syndromes.

In the spine, the fulcrum of the first class lever of upright posture is primarily the vertebral body/disc, and the two facet joints. Pertaining to the head/neck complex, the load is the weight of the head multiplied by the distance between the center of mass of the head and the fulcrum. The effort is the amount of force generated by the contracting muscles on the opposite side of the fulcrum to keep the lever from falling over. This constant muscle contraction with more effort creates muscle fatigue and myofascial pain syndromes.

Rene Cailliet, MD, nicely explains these concepts in his 1996 book Soft Tissue Pain and Disability (6). Pertaining to the loss of cervical lordosis causing a forward head posture, Dr. Cailliet notes that a 10 lb. head with a displaced center of gravity forward by 3 inches would required counter balancing muscle contraction on the opposite side of the fulcrum (the vertebrae) by 30 lbs. (10 lbs. X 3 inches):

Rene Cailliet, MD, nicely explains these concepts in his 1996 book Soft Tissue Pain and Disability (6). Pertaining to the loss of cervical lordosis causing a forward head posture, Dr. Cailliet notes that a 10 lb. head with a displaced center of gravity forward by 3 inches would required counter balancing muscle contraction on the opposite side of the fulcrum (the vertebrae) by 30 lbs. (10 lbs. X 3 inches):

The constant muscle contraction required to keep the head upright when the patient has a loss of cervical lordosis creates muscle fatigue and myofascial pain syndromes (6).

Additionally, the loss of cervical lordosis creates constant, significant increased loads on the fulcrum tissues (discs and facet joints). The consequence of this is accelerated articular deterioration, degenerative joint disease and spondylosis (1, 7, 8, 9).

Spinal Cord Tethering

Beginning in the 1960s, Swedish neurosurgeon Alf Breig, MD, began to document that loss of cervical lordosis (he referred to it as cervical anteflexion), could compromise the vascular integrity of the spinal cord as a consequence of abnormal spinal cord stretching, or tethering (10, 11). Today (9/6/2016) a search of the US National Library of Medicine using the key words “spinal cord tethering” in PubMed located 28,269 citations. Dr. Breig and others note that restoration of cervical spine lordosis immediately results in improved spinal cord blood flow (10, 11, 12). It is suggested that spinal cord tethering and consequent spinal cord ischemia might be a factor in demyelinating disease (12).

Cervical Spinal Cord Myelopathy

A number of researchers have documented that long-standing loss of cervical lordosis, if uncorrected, will lead to cervical spinal cord myelopathy (9, 13, 14, 15, 16). These researchers suggest that the myelopathic findings may be due to vascular compromise (primarily from the anterior spinal artery) or secondary to direct and prolonged pressure on spinal cord neurons.

Regardless of the precise causative mechanism, cervical spinal cord myelopathy secondary to loss of cervical lordosis is a serious/debilitating problem that may have a simple solution for improvement (discussed below).

Vertebral Artery Tethering, Compromise

Earlier this year (2016), a unique study was published in the journal Medical Science Monitor, and titled (17):

Decreased Vertebral Artery Hemodynamics
in Patients with Loss of Cervical Lordosis

This is the first study to focus on the status of the vertebral artery in patients with loss of cervical lordosis. The authors evaluated a number of vertebral artery flow values in patients with loss of cervical lordosis, and compared them to strictly matched control subjects without loss of cervical lordosis. Thirty patients with loss of cervical lordosis and 30 carefully matched controls were assessed bilaterally (60 arteries in each group) with Doppler ultrasonography. Vertebral artery hemodynamics, including lumen diameter, flow volume, and peak systolic velocity were measured, and values were statistically compared between the patient and the control groups.

The cervical lordosis was assessed on lateral cervical radiographs using the posterior tangent method; the lordosis was defined as the angle between the posterior margins of the vertebral bodies C2 and C7.

Vertebral artery hemodynamics was measured in the supine position with the head rotated 45 degrees to the contralateral side. All measurements were repeated 3 times. The authors make these important points:

“The normal cervical spine has a lordotic curve. Abnormalities of this natural curvature, such as loss of cervical lordosis or cervical kyphosis, are associated with pain, disability, and poor health-related quality of life.”

The “natural lordotic curvature of the cervical spine is considered to be an ideal posture in terms of biomechanical principles.”

“Loss of cervical lordosis causes disrupted biomechanics, triggering a degenerative process in the cervical spine.”

“Deviations from the natural curvature may originate from disrupted biomechanics, because axial load is shifted from posterior to anterior column as lordosis is lost, and the increased compressive forces trigger and accelerate the degenerative process.”

“The loss of cervical lordosis is associated with neck, upper thoracic, and shoulder pain, tension and cervicogenic headaches, and poorer health-related quality of life outcomes.”

In addition to bony structure changes in the cervical spine, when the “natural cervical curvature is disturbed, the normal distribution of neck muscle loads is also disrupted and a larger workload is placed on the supportive soft tissues across cervical segments to maintain biomechanical integrity.”

The vertebral arteries proceed in the transverse foramen of each cervical vertebra. “The vertebral arteries are the major source of blood supply to the cervical spinal cord and brain stem.”

FINDINGS

When the cervical curve flattens, the vertebral arteries “are also in danger of being stretched or compressed.”

“The means of diameter, flow volume, and peak systolic velocity in patients were significantly lower as compared to controls.”

“The present study revealed a significant association between loss of cervical lordosis and decreased vertebral artery hemodynamics, including diameter, flow volume, and peak systolic velocity.”

The results of the study revealed that vertebral artery parameters were “significantly different between groups, with patients with loss of cervical lordosis showing lower values in comparison to controls.”

Loss of cervical lordosis adversely affects vertebral artery hemodynamics. This article increases the awareness of the adverseness of loss of cervical lordosis. It also highlights the importance of improving and/or correcting cervical lordosis.

Summary Syndromes

This review presents evidence linking loss of cervical lordosis to:

  • Muscle fatigue and myofascial pain syndromes
  • Accelerated degenerative spinal joint disease, spondylosis
  • Tethered cord syndrome
  • Cervical spinal cord myelopathy
  • Vertebral artery vascular compromise

Solutions

Improvement/restoration of cervical lordosis is an important clinical goal. For decades, biomechanically based chiropractors have recognized the adverseness of loss of cervical lordosis. A number of chiropractic techniques are used to improve cervical lordosis. There are several studies in the US National Library of Medicine (searchable using PubMed) indicating that chiropractic can improve loss of cervical spine lordosis, and even reverse cervical kyphosis. The procedures usually involve combinations of certain adjustments, extension traction, and exercise (18, 19, 20, 21, 22, 23, 24, 25, 26, 27).

Most recently (August 30, 2016, Epub), Egyptian physical therapists Ibrahim Moustafa and Aliaa Diab collaborated with American chiropractor Deed Harrison. Their article was published in the European Journal of Physical and Rehabilitation Medicine, and titled (28):

The Effect of Normalizing the Sagittal Cervical Configuration
on Dizziness, Neck Pain, and Cervicocephalic Kinesthetic Sensibility:
A 1-Year Randomized Controlled Study

In this study, the authors assessed the improvement of cervicogenic dizziness symptoms by improving cervical spine lordosis. The study was a yearlong randomized controlled study involving 75 cervical spine hypolordotic subjects. The rehabilitative approach showed that substantial improvement in cervical lordosis was achievable, and study subjects showed significant improvement in dizziness severity, dizziness frequency, and neck pain. The authors concluded:

“Appropriate physical therapy rehabilitation for cervicogenic dizziness should include structural rehabilitation of the cervical spine (lordosis and head posture correction), as it might to lead greater and longer lasting improved function.”

•••••••••

Conclusions

Optimal spinal function requires an appropriate cervical lordosis. For half a century, researchers and clinicians have linked the loss of cervical lordosis to a number of chronic clinical syndromes, including myofascial pain syndrome, spinal arthritis (spondylosis), tethered cord syndrome, cervical spinal cord myelopathy, and vertebral artery vascular compromise.

Loss of cervical spinal lordosis is radiographically measurable. Evidence indicates that loss of cervical lordosis is epidemic and a growing problem. Dr. Kenneth Hansraj indicates that the major modern contributor to the problem is the prolonged holding of one’s head down and forward while using cellular devices. He indicates that these devices are used approximately 5,000 hours yearly by teenagers, and 1,800 hours yearly by adults. This indicates that the incidence of these postural distortions is not going to go diminish any time soon.

Chiropractors can be the most important health care provider in dealing with the loss of the cervical lordosis issue. They can quantify the problem radiographically; they can ergonomically and habitually coach the patient towards better postural habits; they can improve cervical lordosis with a variety of clinical approaches and home care advice.

REFERENCES

  1. White AA, Panjabi MM; Clinical Biomechanics of the Spine, Second Edition; Lippincott; 1990.
  2. Hansraj KK; Assessment of Stresses in the Cervical Spine Caused by Posture and Position of the Head; Neuro and Spine Surgery, Surgical Technology International; November 2014; Vol. 25; pp. 277-279.
  3. Kapandji IA; The Physiology of the Joints; Volume Three, The Trunk and the Vertebral Column; Churchill Livingstone; 1974.
  4. Jackson R; The Cervical Syndrome; Thomas; 1978.
  5. Vincenzo Giuliano V, Concetta Giuliano C, Fabio Pinto F, Mariano Scaglione M; The use of flexion and extension MR in the evaluation of cervical spine trauma: initial experience in 100 trauma patients compared with 100 normal subjects; Emergency Radiology; October 2002; Vol. 9; pp. 249–253.
  6. Cailliet R; Soft Tissue Pain and Disability; 3rd Edition; F A Davis Company; 1996.
  7. Cailliet R; Low Back Pain Syndrome, 4th edition; F A Davis Company; 1981.
  8. Garstang SV, Stitik SP; Osteoarthritis: Epidemiology, Risk Factors, and Pathophysiology; American Journal of Physical Medicine and Rehabilitation; November 2006; Vol. 85; No. 11; pp. S2-S11.
  9. Ozer E, Yücesoy K, Yurtsever C, Seçil M; Kyphosis One Level Above the Cervical Disc Disease: Is the Kyphosis Cause or Effect?; Journal of Spinal Disorders & Techniques; February 2007; Vol. 20; No. 1; pp. 14-19.
  10. Breig A, El-Nadi AF; Biomechanics of the cervical spinal cord: Relief of contact pressure on and overstretching of the spinal cord. Acta Radiol Diagn (Stockh) 4:602–624, 1966.
  11. Breig A; Adverse Mechanical Tension in the Central Nervous System, An Analysis of Cause and Effect; Almquist & Wiksell; 1978.
  12. Wing PC, Tsang IK, Susak L, Gagnon F, Gagnon R, Potts JE; Back pain and spinal changes in microgravity; Orthopedic Clinics of North America; April 1991; Vol. 22; No, 2; pp. 255-262.
  13. Shimizu K, Nakamura M, Nishikawa Y, Hijikata S, Chiba K, Toyama Y; Spinal Kyphosis Causes Demyelination and Neuronal Loss in the Spinal Cord: A New Model of Kyphotic Deformity; Spine; November 1, 2005; Vol. 30; No. 21; pp. 2388-2392.
  14. Uchida K, Nakajima H, Sato R, Yayama TI, Erisa S. Mwaka, Kobayashi S, Baba H; Cervical Spondylotic Myelopathy Associated with Kyphosis or Sagittal Sigmoid Alignment: Outcome after Anterior or Posterior Decompression; Journal of Neurosurgery: Spine; November 2009; Vol. 11, pp. 521-528.
  15. Ruch WJ; Subluxations of the Human Spine and Pelvis, Second Edition; Life West Press; 2014.
  16. Justin K. Scheer JK, Tang JA, Smith JS, Acosta FL, Protopsaltis TS, Blondel B, Bess S, Shaffrey CI, Deviren V, Lafage V, Schwab F, Ames CP; Cervical spine alignment, sagittal deformity, and clinical implications: A review; Journal of Neurosurgery Spine; August 2013; Vol. 19; pp. 141–159.
  17. Bulut MD, Alpayci M, Şenkoy E, Bora A, Yazmalar L, Yavuz A, Gulşen I; Decreased Vertebral Artery Hemodynamics in Patients with Loss of Cervical Lordosis; Medical Science Monitor; February 15, 2016; Vol. 22; pp. 495-500.
  18. Leach RA; An evaluation of the effect of chiropractic manipulative therapy on hypolordosis of the cervical spine; Journal of Manipulative and Physiological Therapeutics; March 1983; Vol. 6; No. 1; pp. 17-23.
  19. Harrison DD, Jackson BL, Troyanovich S, Robertson G, de George D, Barker WF; The efficacy of cervical extension-compression traction combined with diversified manipulation and drop table adjustments in the rehabilitation of cervical lordosis: a pilot study; Journal of Manipulative and Physiological Therapeutics; September 1994; Vol. 17; No. 7; pp. 454-64.
  20. Troyanovich SJ, Harrison DE, Harrison DD; Structural rehabilitation of the spine and posture: rationale for treatment beyond the resolution of symptoms; Journal of Manipulative and Physiological Therapeutics; January 1998; Vol. 21; No. 1; pp. 37-50.
  21. Harrison DE, Harrison, DD, Haas JW; CBP Structural Rehabilitation of the Cervical Spine, 2002.
  22. Harrison DE, Cailliet R, Harrison DD, Janik TJ, Holland B; A new 3-point bending traction method for restoring cervical lordosis and cervical manipulation: a nonrandomized clinical controlled trial; Archives of Physical Medicine and Rehabilitation; April 2002; Vol. 83; No. 4; pp. 447-453.
  23. Morningstar MW, Strauchman MN, Weeks DA; Spinal manipulation and anterior head-weighting for the correction of forward head posture and cervical hypolordosis: A pilot study; Journal of Chiropractic Medicine; Spring 2003; Vol. 2; No. 2; pp. 51-54.
  24. Harrison DE, Harrison DD, Betz JJ, Janik TJ, Holland B, Colloca CJ, Haas JW; Increasing the cervical lordosis with chiropractic biophysics seated combined extension-compression and transverse load cervical traction with cervical manipulation: nonrandomized clinical control trial; Journal of Manipulative and Physiological Therapeutics; March-April 2003; Vol. 26; No. 3; pp. 139-151.
  25. Ferrantelli JR, Harrison DE, Harrison DD, Stewart D; Conservative treatment of a patient with previously unresponsive whiplash-associated disorders using clinical biomechanics of posture rehabilitation methods; Journal of Manipulative and Physiological Therapeutics; March-April 2005; Vol. 28; No. 3; pp. e1-8.
  26. Oakley PA, Harrison DD, Harrison DE, Haas JW; Evidence-based protocol for structural rehabilitation of the spine and posture: review of clinical biomechanics of posture (CBP) publications; Journal Canadian Chiropractic Association; December 2005; Vil. 49; No. 4; pp. 270-296.
  27. Gong W; The effects of cervical joint manipulation, based on passive motion analysis, on cervical lordosis, forward head posture, and cervical ROM in university students with abnormal posture of the cervical spine; Journal of Physical Therapy Science; 2015; Vol. 27; pp. 1609-1611.
  28. Moustafa IM, Diab A, Harrison DD; The Effect of Normalizing the Sagittal Cervical Configuration on Dizziness, Neck Pain, and Cervicocephalic Kinesthetic Sensibility: A 1-Year Randomized Controlled Study; European Journal of Physical and Rehabilitation Medicine; August 30, 2016 [Epub].

“Authored by Dan Murphy, D.C.. Published by ChiroTrust® – This publication is not meant to offer treatment advice or protocols. Cited material is not necessarily the opinion of the author or publisher.” 

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