Someone felt my disc was out and pushed it back in! .....REALLY?! What does the science say?
I thought that I would write this blog article to clear a few things up about what some patients are told by some therapists.
The common thing that I hear from patients is that the therapist felt the discs were out, or were calcified and then performed a technique and go on to say that they are back in after the technique.
Now I don't know where to start with this because it's just not possible based on normal human anatomy. The thing that perpetuates the myth is that whatever technique is used it can bring about symptom improvement, which I don't dispute at all. However, the statement about what it has done and why it has done it are so far off base it's crazy!
So answering the first question: Can you palpate a disc?
I'll let the pictures illustrate the answer below:
The first problem is the depth. Look below at how deep into the body that disc is! It is not far off half way to your middle. So even if all the stuff in the way was soft and gooey and you could simply push your finger in to where the disc is, your finger would be too short!
The next problem is that the 'stuff' above it isn't soft and gooey, it's tough and hard! You have skin, fascia, muscle, ligament and bone to get though.
Fascia for example is made of collagen, which is extremely tough and this makes fascia very tough. This makes it nearly impossible to move, which is supported by Chaudhry et al (2008).
If you look below, where the fascia, muscle and ligaments are removed the amount disc that you can see is very small so even if the above issues weren't there then you would have to be very accurate to feel it.
So the fact that you can't feel it means that you can tell if they are 'out', calcified or anything else and for the same reason you can't just push them back in place.
Even if you could push on them, the problem then would be that they are very hard structures that don't move easily. This is highlighted by Adams et al (2000) who found that 2° of Lumbar extension increased the maximum compressive stress within the posterior anulus of the disc by an average of 16%, compared with a neutral standing posture. It was found that disc force is 404 Newtons on L5 in standing according to Shirazi-Adl et al (2005), which is 41kg.
So arching your back to just 2 degrees would place 48kg of force on the L5 disc. Now i'm pretty sure that you would struggle to place this force onto the disc by hand even if you had very long fingers that could pass through skin, fascia, muscle, ligament and bone!
Summary:
So in summary you can't touch a disc, tell what state it is in or move it by hand but they can be assessed by a good subjective and objective examination and can be helped by the correct movements of your own body.
Take home message is don't believe everything that you hear, except from me of course LOL!
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