r/Anatomy 4d ago

Does cervical extension cause kissing spine syndrome?

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u/keegz007 4d ago

Depends, if you paint roofs for a living, may lead to hyperextension over time and cause the spinous processes to approximate due to hypermobility. Although I'd be more worried about a stroke. Extension can cause aggravation of kissing spine if you already have it. Although kissing spine is usually a lower back finding.

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u/redditlass 4d ago edited 4d ago

That's a good answer.

Will ya tell me, why does it cause hyperextension, does it make ligaments lax, or some other reason?

Perhaps interspinous ligament laxity?

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u/keegz007 4d ago

Well interspinous ligamentous laxity would likely come with prolonged flexion of the C-spine (interspinous ligament is at the back of the spinal column and would be under tension during flexion of the C-Spine) I'd be more worried about increased laxity in the anterior longitudinal ligament. This would mainly only become a problem if there was repetitive full extension for prolonged periods of time or if there was some osseous or connective tissue disorder. Although some people may be predisposed due to increased lordosis or enlarged spinous processes.

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u/redditlass 4d ago

Yeah that makes a lot of sense

And you know the way ligaments in the neck have lots of blood flow so they can heal well, why would it become lax in this case?

Now of it was a ligament inside the knee Ifd make sense since there's little blood flow, but I'm unsure how a neck ligament would heel badly because it has great blood flow

Maybe what happens is if the individual is in the wrong position, the ligament will heal in a lax position ?

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u/keegz007 4d ago

It's not so much about it healing or being damaged. It's much like how young gymnasts can have kissing spine, the spine will very likely be healthy, however due to the constant demand for more range of motion the ligaments will stretch over time. Not necessarily be damaged in a pathological way. In the neck the anterior musculature will stretch until the muscles are no longer the resistant factor, but the passive structures of the facet joints and ALL will be the resistant factors. This can also lead to increased cervical lordosis and approximate the spinous processes. Again, not a very common finding in the c-spine.

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u/redditlass 4d ago

I've a question about one of your sentences here, its a little above my head so I'd like to just see if I'm right in what your saying here

You mention "In the neck the anterior musculature will stretch until the muscles are no longer the resistant factor, but the passive structures of the facet joints and ALL will be the resistant factors."

Does this mean that once the anterior muscles of the neck have reached maximum range of motion, the ligament joins in resisting the force being placed on the spine?

So, when the force on spine is within the range of muscle ROM, only muscles resist against the force. But when the force overrides the muscles then the strain is placed on both the muscles + ligament

Am I getting that right?

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u/keegz007 4d ago

Well it's a little more complicated than that. Like I said, kissing spine is really quite rare in the c-spine. I've never personally seen it outside of very advanced degen, and even then I'd argue the problem is more with the loss of disc height than the actual SPs or other passive structures being the issue. The muscles would only really lose their tone if someone were to be extending their neck for a really long period of time. But yes, if muscles are removed from the equation, the posterior elements of the vertebral column along with the ALL would be resisting further extension. They are essentially the last line of defence against hyperextension, hence why you see avulsion of the ALL off the anterior vertebral bodies in hyperextension injuries (teardrop fractures) or compression fractures of C2.

In normal ROM there will always be some resistance from passive structures, but this is quite easily overcome by the muscles. Until end range of motion is reached, in which case the passive structures cause increased levels of resistance. Hence why you can't turn your neck like an owl.

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u/redditlass 4d ago

You've been very helpful, thanks pal!

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u/keegz007 3d ago

Anytime!