Sacroiliac Joint Injury and Piriformis Pain

Every Step You Take – Every Move You Make

Can Your Sacroiliac Joints Take the Stress?


It all comes down to the prin­ci­ples of engi­neer­ing.

When you’re stand­ing up, grav­i­ty is pulling the weight of your tor­so straight down.

For­tu­nate­ly, you have two legs and two feet to sup­port you.

Unfor­tu­nate­ly, they’re off to each side.  Nei­ther of them is direct­ly under your cen­ter of weight.

Roman engi­neers designed arch­es to hold up a struc­ture using sup­ports on each side. How does your body pull off this feat of engi­neer­ing design?

Sacroiliac Joint Injury & The Roman Arch

In your body, the cen­tral ver­ti­cal force of grav­i­ty is trans­mit­ted through the sacroil­i­ac joints on either side.  They link the sacrum to the hip bones.

Then, as the song goes, the hip bone’s con­nect­ed to the thigh bone, and so forth and so on down to your feet.

Sacroiliac Joint

What can go wrong with this bril­liant sys­tem?

Shear stress.

The body has been designed to cope with lots of phys­i­cal stress­es.  For exam­ple, the force of com­pres­sion – in the lum­bar spine, for instance — squash­es the ver­te­brae togeth­er, squeez­ing the disc in between.

Shear stress, on the oth­er hand, is a force that tries to make one bone side-slip rel­a­tive to its neigh­bor.  In the sacroil­i­ac joint it’s easy to visu­al­ize the effect.  Your body weight is try­ing to force the sacrum down­ward between the two hip bones. (The ili­um — plur­al ilii — of the pic­ture above).

The sit­u­a­tion is chal­leng­ing enough when you’re stand­ing on both feet.  When you’re walk­ing, each step involves shift­ing to one-sided weight-bear­ing.  That focus­es all the shear stress on one sacroil­i­ac joint at a time.

How the Body Adapts to Shear Stress of the Sacroiliac Joint

First, the well-orga­nized body min­i­mizes shear stress by engag­ing core sup­port – con­tract­ing the oblique and trans­ver­sus abdom­i­nal mus­cles to lim­it the amount of side-to-side weight shift with each step.  This reduces the stress on the sacroil­i­ac joints.

Sec­ond – con­tract­ing your hip rota­tors (i.e. the pir­i­formis mus­cle) cinch­es togeth­er the sacroil­i­ac joint as you shift your weight onto it.  This sta­bi­lizes the sacroil­i­ac joint so it can bet­ter accom­mo­date shear stress.

Third – the tough lig­a­ments span­ning the sacroil­i­ac joint itself are the body’s last line of defense against shear stress.  Unfor­tu­nate­ly, when your first two cop­ing mech­a­nisms aren’t work­ing robust­ly, too much stress is placed on the sacroil­i­ac lig­a­ments.  The result is pain or injury.  Over the years, as your lig­a­ments lose their resilience and dete­ri­o­rate with age, your mar­gin of safe­ty becomes small­er and sacroil­i­ac pain becomes more like­ly.

Preventing Sacroiliac and Piriformis Pain

  1. the plank pose strength­ens your core mus­cles and trains your brain to engage them effec­tive­ly
  2. bal­anc­ing exer­cis­es on one leg devel­op sup­port­ive strength of the Pir­i­formis
  3. when stand­ing, avoid sag­ging onto one leg
  4. when car­ry­ing, hold the weight on alter­nate sides
  5. stretch­ing the pir­i­formis will help keep it in top shape

Your Doctor of Chiropractic Can Help Protect You from Sacroiliac and Piriformis Pain

Your doc­tor of chi­ro­prac­tic is unique­ly qual­i­fied to

  1. Make sure you’re using good prin­ci­ples of move­ment orga­ni­za­tion when you stand, walk, or car­ry
  2. Rec­om­mend and review core sup­port exer­cis­es with you
  3. Ana­lyze and cor­rect align­ment prob­lems in the feet, knees, hip, or spinal joints that could lead to pelvic imbal­ance and increased sacroil­i­ac stress
  4. Fash­ion cus­tomized foot orthotics to bal­ance forces affect­ing the sacroil­i­ac joint
  5. Man­u­al­ly release trig­ger points in the pir­i­formis mus­cle
  6. Ana­lyze and cor­rect an altered or restrict­ed pat­tern of glide in the sacroil­i­ac joint


Deepen Your Body of Knowledge

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About Ronald Lavine, D.C.

Dr. Lavine has more than thirty years' experience helping patients alleviate pain and restore health using diverse, scientifically-based manual therapy and therapeutic exercise and alignment methods.

His website,, provides more information about his approach.

Please contact him at or at 212-400-9663.

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