The Sacroiliac Joint

Don’t Tell This Lady There’s No Movement At The Sacroiliac Joint 

Most injuries happen in the areas between the major weight segments of the spine — atlanto-occipital, cervico-thoracic, lumbosacral. An additional segment to consider in low back, leg and gait problems is the sacroiliac joint, situated between the low back and the hips.  

Traditional anatomy ascribed no movement whatsoever to the sacroiliac joint, and considered the S/I to be part of a unitary pelvis. Like the innominate bone (“innominate bone” means “the bone with no name” – only a bonehead would name such a bone with such a name), the pelvis as a whole was discussed as several bones, but treated operationally as one. 

Clearly, they didn’t consult dancers, generally hypermobile in their joints, who use their sacroiliac joints so much that they often endure excruciating pain when they do extreme hip joint movements like arabesque, split leaps and holding the leg high in the air while standing on a pointe shoe. (Oy!) 

Movement-centered touch professionals began to argue, and it is now accepted, that the sacroiliac joint was moveable and played a significant role in assisting the action called “hip flexion” and a smaller role in “hip extension”.   

It’s easy to view this as a minor semantic distinction, like theologians arguing about the number of angels you could fit on the head of a pin. But for the practitioner, it’s important, and the reason is that this joint is crucial for healthy movement.  

[Keep this in mind: it’s important to understand anatomy, but as practitioners, our goal is to use anatomy to understand and assist function. (“Anatomy” is a science of structure derived from cutting open a dead body; “kinesiology” is about how anatomy operates in movement, or more specifically, in life.)] 

Thinking of a mobile S/I joint changes our whole idea of how the legs and the trunk relate to each other. In traditional anatomy, we have a spine (rooted in the pelvis), and legs, which move relative to the pelvis in gait. When we add a moving sacroiliac joint to the skeleton, we also have the option to use my mentor Irene Dowd’s concept of “no pelvis”, seeing the sacrum as part of the spine and the “innominate bones” as belonging to the legs. (I like to call the ilia the “mouseketeer ears” of the pelvis, but that’s just me.) In this context, a much more dynamic relationship between the body and the legs is invoked, and Dowd’s concept of dynamic stability (which, to me, is a function-oriented way to think of “core strength”) becomes much more easy to imagine kinesthetically.  

For more information and a video, see my article in Massage Journal: https://user-35215390377.cld.bz/Massage-Therapy-Journal-Spring-2024/20/