Tuesday, October 6, 2009

Cervical Posture and Consequences

I've talked before about forward head posture and some exercises to help correct it. This will get a little more anatomical. We all know that cervical posture is important, but do you know how important? We all have seen the classic forward head posture, chin sticking out at the world. On the flip side, you have military neck. Straight up and down. Let's look at some implications of poor posture.

First, forward head posture goes hand and hand with rounded shoulders. When the shoulders round, the body must shift the center of gravity of your head forward for balance. As the head comes forward what is happening anatomically?

1. There is an increase in lordosis. (curve of the spine) This will put increased stress to the cervical facet joints. This in turn will also put the articular cartilage at risk, which can lead to arthritic change.

2. The increased lordosis will also increase the shear force in the neck, this puts your discs more at risk.

3. The increase in forward head posture forces the mid cervical spine into hyperextension. This puts a lot of stress at the C4-C5 and C5-C6 joints.

4. C2-C3 are also put under much stress, because of the narrowing at the intervertebral foramina. (where the nerve exits) This can lead to stress on the nerves and recurrent chronic headaches.

5. The SCM, levator scapulae and upper trap shorten, which results in an elevated scapulae.

When the opposite occurs and the spine straightens, commonly called military neck cause other problems.
There is a balance between compressive and shear forces on the disc when your posture is good. When it's faulty, forward head posture increased shear. When the spine straightens, the load is straight up and down so your compressive force on the disc increases.

In the next post we'll go over some corrective exercise strategies to help balance out the body.

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