5 Causes of a Straight (or Reversed) Neck Curve

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Spinal Curves - Why We Have Them

Spinal curves alternate directions in adjacent regions.
Spinal curves alternate directions in adjacent regions. decade3d

Our spinal columns are not straight.  Instead curves alternate down the column according to main regions: Cervical (neck), thoracic (mid and upper back), lumbar (low back) and sacral (corresponding to the sacrum bone.)

This means that some spinal curves move into one direction, and others to the opposite.  If you were to look at the spine from a side view (see the leftmost image above), you'd see that the neck and low back curves sweep forward while the thoracic and sacral curves protrude back.  

This is by design:  Opposing curves provide you with the ability to support and balance your body weight during all kinds of actions.

The curve in your neck is called a lordosis, which means that from a side view it sweeps toward the front.  (The curve in the low back is also a lordosis.)  The cervical lordosis develops in babies once they begin lifting and supporting the weight of their head.

Loss of Cervical Curve, Cervical Kyphosis or, aka, Military Neck

What happens when something comes along to alter the natural lordosis in your neck, perhaps causing it to become straight or even reverse?  This condition is known as a cervical kyphosis, loss of cervical curve or military neck.  

Loss of cervical curve may up your risk for future neck problems that could involve your spinal cord. 

But the good news is that cervical kyphosis does not seem to correlate with neck pain.  A 2007 study by Frauenfelder, et al, published in the European Spine Journal compared the x-rays of two groups of people over the age of 45  who happened to be at a hospital for an unrelated issue.  The groups consisted of those with neck pain and those without.

The researchers found no significant differences in structural factors between the two groups.  In other words, neither the global curve measurement, the segmental angle (segmental refers to one vertebral level) measurements, nor the incidence of a straight spine or reversed curve in the neck in either group showed a relationship to neck pain.

Related: What is a Motion Segment?

Source:

1. Grob D, Frauenfelder H, Mannion AF. The association between cervical spine curvature and neck pain. Eur Spine J. 2007;16(5):669-678. doi:10.1007/s00586-006-0254-1.

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Does Degenerative Disc Disease Cause Cervical Kyphosis?

Cervical kyphosis is a reversing of the natural curve in the neck (or low back.)
Cervical kyphosis is a reversing of the natural curve in the neck (or low back.). plepraisaeng

Degenerative disc disease is another cause of cervical curve loss.  As we age, our discs dry out which decreases their height.  The increasing lack of buoyant support available from discs may encourage  your head to tilt forward.  This altered head and neck posture will likely, over time, contribute to a loss of cervical curve.

The reverse may be true as well.  A 2009 study by Okada, et. al, and published in the European Spine Journal followed 113 people for at least 10 years and found that a straight or kyphotic cervical spine may be responsible for speeding degenerative changes that occur in the neck. The study did not find a correlation between a straight or curve-reversed spine and symptoms, though.

Source:

1. Okada E, Matsumoto M, Ichihara D, et al. Does the sagittal alignment of the cervical spine have an impact on disk degeneration? Minimum 10-year follow-up of asymptomatic volunteers. Eur Spine J. 2009;18(11):1644-1651. doi:10.1007/s00586-009-1095-5.

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Birth Defects

One type of cervical kyphosis is congenital.
One type of cervical kyphosis is congenital. cookelma

Loss of cervical curve can be caused by a birth defect that is related to a failure of formation somewhere in the spine.  This is called congenital kyphosis.  

Congenital kyphosis usually also leads to disordered growth in the vertebrae (spinal bones) where they develop into a triangular wedge shape when viewed from the side - rather than the typical square shape.  The resultant triangular shape of the vertebrae causes the spine to round forward, creating kyphosis.  Congenital kyphosis is usually accompanied by birth defects in the kidneys and urinary system, as well.

Treatment for congenital cervical kyphosis is usually surgery.  If, for whatever reason, you decide against surgery, close medical observation and follow up is a must for preventing serious problems, according to the University of Maryland Medical Center.

Sources:

University of Maryland Medical Center. A Patient's Guide to Cervical Kyphosis. Cervical Kyphosos. University of Maryland Medical Center website.

Zeng Y, Chen Z, Qi Q, et al. The posterior surgical correction of congenital kyphosis and kyphoscoliosis: 23 cases with minimum 2 years follow-up. Eur Spine J. 2013;22(2):372-378. doi:10.1007/s00586-012-2463-0.

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Neck Injury and Trauma

Injury is one cause of cervical curve loss and kyphosis.
Injury is one cause of cervical curve loss and kyphosis. Klanneke

 Injury and trauma  to the spine can cause cervical kyphosis, too.   Vertebrae that sustain compression fractures, for example, often develop into a triangular shape during the healing process. As with congenital kyphosis, the triangularly shaped bones may result in a forward curve in your neck.  (In extreme cases, this condition may lead to spinal stenosis.)

Related:  What is Central Canal Stenosis?

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Medical Treatments and Spine Surgery

One type of cervical curve loss is iatrogenic.
One type of cervical curve loss is iatrogenic. kovalvs

Another potential cause of cervical curve loss is medical error, called "iatrogenic."  The University of Maryland Medical Center says that two types of surgery - laminectomy and fusion - may place you at a higher risk.

Related:  Laminectomy

In a laminectomy, a portion of the ring of bone in back is removed to make room for nerves to pass unimpeded.  Problem is, removing this area of the ring can interfere with the stability of the nearby facet joints.  This, in turn, may cause the cervical spine to tilt forward into a kyphosis.

Related:  Learn About Your Facet Joints

A spinal fusion that involves only a few bones (called a "short fusion) may create a postural adaptation in which the spine bends over the topmost bone that's been fused.  This, of course, can lead to cervical kyphosis.

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Other Causes of Loss of Neck Curve

Infection or systemic disease is a cause of reversed cervical curve.
Infection or systemic disease is a cause of reversed cervical curve. Leonardi

Other causes of loss of cervical curve and/or cervical kyphosis include tumor, infection, and systemic disease such as anklyosing spondylitis.  Prior radiation treatment for cancer may also cause cervical kyphosis.

Related:  What is Axial Spondylitis?

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