I can feel twin bumps on either side of my lower spine which I believe are protrusions from the iliac crest -- approximately where the erector spinae appear to originate. I can generate pain in this region by sitting with my legs straight out in front of me and rotating one toe toward the other. Does this match the function of any specific muscle or tendon? I am unable to search for stretching exercises because I can't name the body part.

  • 2
    See if these are the twin bumps you are describing. If so, this is part of the SI (sacro-iliac) joint, not a muscle. If you have pain here, you may want to check with a physio and ask about Don Tigny mobilizations and exercises. Commented Jun 29, 2014 at 13:04
  • Thank you for correctly identifying the bumps. I will ask about Don Tigny if it turns out to be the joint rather than radiating from a muscle.
    – Noumenon
    Commented Jun 29, 2014 at 15:50

2 Answers 2


You would probably benefit from having a physical therapist's or chiropractic evaluation.
If you prefer to try to figure it out on your own search the site for piriformis for more information.

Since you've identified the bumps as the PSISs, and you reproduce your pain by rotating your foot (actually the hip into internal or medial rotation), look at the muscles that attach to the sacrum (which is part of the SI joint).

You will see that there are 6 muscles that laterally (externally) rotate the hip (toes out away from each other) with the piriformis attaching to the sacrum. If these are tight and you try to turn your toes inward, you pull on the lateral rotators that attach to the sacrum and can put a stress on the SI joint. The muscles work differently if the hip is flexed or extended.

You can stretch these muscles. You can massage these muscles. However, it is worth seeing a professional to have an evaluation and to set you up with appropriate stretches, strengthening exercises, and massage techniques with either a tennis ball/and or foam roller. A professional would be able check your alignments and isolate which muscles are weak and which are tight and decide if you need any stabilization. Hope that helps.

  • I looked up a bunch of stretches for those six muscles... I had been planning to find out as much as I could about the muscles so I could tell a professional my history, now I'm a little tempted to just stretch all the things and see if it's enough. Kind of the reverse of my first approach where I went to physical therapy and didn't do the stretches.
    – Noumenon
    Commented Jul 1, 2014 at 21:19
  • 1
    If you've had an accident you should really go by what your therapist says. It can be an ongoing process depending on what you hurt. As you can tell by looking at the muscles and the pelvis, it is complicated. But now that you have researched and have a better idea you will probably get more out of therapy and make better progress. Good luck. Commented Jul 3, 2014 at 10:30

That is the "glute-med" as is colloquially referred to, more formally it is the gluteus medius.

To loosen this area try getting a "bumpy ball" and rolling it around there. Try not to use something like a lacrosse ball. This muscle is too small to safely withstand a lot of pressure from a single point.

As stated in a comment above, the issue may actually be with the SI joint and a professional should be consulted for further aid.

  • See the edits..
    – user9941
    Commented Jun 29, 2014 at 15:26
  • I confirmed that foot rotating is the function of the gluteus medius and that my gluteus medius is weak on the affected side. I can create some hip pain by standing on my left leg and pressing my right hip against the wall with the gluteus medius. However, the original pain I can produce by rotating the foot when I do a single leg extension is more medial, right by or inside the twin bumps. I'll probably accept your answer about the muscle but it sounds like my problem may be in a joint.
    – Noumenon
    Commented Jun 29, 2014 at 16:12
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    Correct, I did answer the questioned you asked, but I do think that @BackinShapeBuddy gave a great piece of advice about identifying the bumps and the relation to the SI joint.
    – user9941
    Commented Jun 29, 2014 at 16:17
  • Ever since my accident my back has gone nuts while walking backwards. By activating the weak gluteus medius on that side I can walk backwards normally without muscles pulling and spine cracking. Thanks.
    – Noumenon
    Commented Jul 1, 2014 at 21:20

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