What do you think of this idea? It came to mind as I was working with my hip impingement/lumbar spine pain athlete. He has iliosacral/sacroiliac issues. I'm doing MET to correct them, but knowing damn well it is only temporary.
Ben Kibler MD came up with the "scapular funnel" concept of the upper extemity. That is, the scapula transmits forces coming through the lower extremity & torso to the ipsilateral arm. But, it's reactions are only as good as the information coming in. In the computer industry they call it "garbage in/garbage out".
I think the same might be said of the sacrum. As in the scapula, dysfunctions in the IS/SI joint doesn't always manifest itself in pain directly on the joint. I've seen in the literature stress fx's of the sacrum in distance runners, which might back up my hypothesis.
The big researchers on this joint are Kaltenborn, Vleeming, and Schneiders. It's interesting stuff.