The following came to me via a comment on a recent post on thoracic mobility. I found it to be quite interesting and felt is deserved to be a answered in the blog rather than in the comments section. Read this question with great caution as it’s pretty scary:
Mr. Hartman,
When you talk about Thoracic spine mobility are you referring to the flexibility in the musculature or the mobility of the vertebrae themselves. I recall a few weeks back in one of my graduate classes my professor was very clear in stressing the point because the thoracic vertebrae were attached to the sternum, via the ribs, that there was no measurable movement within these joints. He then demonstrated with a model that the only freely movable vertebrae were in the cervical and lumbar regions. Just want to be sure I’m understanding what you mean exactly by mobility. Thoughts?
Thanks for your time.
I am very concerned over your question. I am hoping that it’s a misinterpretation of what your professor explained rather than a true representation of what you’re being taught at a graduate level. Let’s review a little bit about thoracic spine mobility.
If your statement in regard to your professor’s comments is true, then I’m afraid your professor is dead wrong.
While it is true that thoracic spine mobility is restricted by the ribcage (one of the reasons why <1% of disc herniations occur in the t-spine is because the ribcage does a good job of limiting spinal flexion), it is far from immobile.
The upper thoracic spine
The zygapophyseal joints of the upper thoracic spine are orientated toward the frontal plane. This limits spinal flexion to about four degrees per segment from T1-T6, but it allows about 8 degrees of rotation per segment from T1 to T8. From T1 to T10 you’ve got roughly 6 degrees of lateral flexion per segment.
The Lower Thoracic Spine
Because the zygapophyseal joints change orientation to a more sagittal plane alignment in the lower t-spine, the ability to flex increases from about five to about 12 degrees per segment as you work your way down from T6-7 to T12-L1. The orientation of the joints also limits rotation to about 2 degrees per segment below T10.
So you can see that while movement is restrained by the anatomy, the thoracic spine does move quite a bit. In fact a loss of mobility in the the thoracic spine can lead to neck, shoulder, lower back, and even lower extremity dysfunction and pathology. This is one of reasons we spend so much time working mobility drills from Inside-Out and Assess and Correct in my clinic and at IFAST.
I would suggest that you research spinal mobility yourself and challenge your professor to prove or clarify his point. Also, seek out resources that show how a reduction in thoracic spine mobility reduces shoulder range of motion and shoulder girdle posture. At worst, you’ll get the correct information, and at best, you’re professor may learn something and change his tune a bit.
Best of Luck.
Bill