Knee "popping"

[Superfoot]

When I get to 6~8 inches off the floor in a side split, my right knee makes a dull (but audible) "pop" sound, similar to the sound made when cracking knuckles. It causes no pain. Any idea what this could be?

[trae]

I have a similar problem when I go down into a very low squat. Vigorous stretching seems to alleviate it, so I've had to conclude that it's tightness somewhere..

[SimonG]

The 'popping' noise you hear is most likely the movement of a bursa within the synovial fluid of the joint. This is what causes the noise when cracking knuckles as the bursa (a small air pocket) is squeezed through the tight space available in the joint. If indeed this is the cause, it is nothing to be concerned about as it is quite common in all joints within the body, particularly in people who are more active, which I assume you are if you are an avid reader of this forum.

The fact that the problem is alleviated by vigourous stretching is more likely to be as a result of the fact that you have warmed up somewhat during the vigourous stretching, rather than an indication of any tightness anywhere.

If however the popping noise is accompanied by any kind of pain, you should consult a medical professional. I cannot stress this enough!!!!

Hope this helps, or at least puts your minds at rest.

[Thomas Kurz]

The 'popping' noise you hear is most likely the movement of a bursa within the synovial fluid of the joint. This is what causes the noise when cracking knuckles as the bursa (a small air pocket) is squeezed through the tight space available in the joint.

What is this? A creative anatomy?

For descriptions and illustrations of various bursae see human anatomy books or atlases.

For info on sounds in and around joints see pages 158-161 in Stretching Scientifically.

[SimonG]

Mr Kurz,

Can you please explain your creative anatomy comment? At the time I wrote my response, I did not have my copy of Stretching Scientifically at hand (I made the mistake of lending it to a friend) and was therefore unable to refer Superfoot to the relevant page number. I have no wish to dispute your knowledge on the subject, nor do I claim to possess anywhere near the same level of knowledge. I simply provided a possible explanation that I had previously received when I asked an orthapedic surgeon a very similar question. I did not question his advice (because he is a surgeon) but would be curious to know what aspect of his (and subsequently my) advice is incorrect.

I am generally reluctant to respond to any questions posed in this forum, as I concede that there are others far more knowledgeable and experienced than I, however in this case Superfoot's question had remained unanswered for four weeks, and I therefore thought my response may alleviate any unfounded concerns he may have. You may have noted that I did also suggest that if he had any pain associated with his problem that he seek professional medical advice and not rely on my evidently quite amateurish understanding of the issue.

I have the utmost respect for your vast knowledge on this subject and would like to know where I may have been previously misguided.