The SI Joints and Low Back
Low Back and Pelvis 101
Within the yoga craft, we cultivate a deep understanding of anatomy, how the body works + how to care for it. This is empowerment.
Lately, I’m hearing a recurrent conversation around low back pain. Let's de-mystify the low back and pelvis.
We have a triangular-shaped sacrum, at the base of the spine, which is composed of 5 fused vertebrae & meets wing-shaped ilium bones (our largest pelvic bones). This junction births our sacroiliac (SI) joints. Here, we find a co-dependent relationship: a convex sacrum & a concave ilium are birthed to us fairly smooth- but as we moove & groove over time, each intelligently rides the wave of the other until we are left with our own unique "fit." While the interplay between these two joints yields balance & cohesion, it also invites vulnerability.
Ahhh, the capricious sacroiliac (SI) joints. We have 2, and along with our hip joints, the SI joints provide a suspension-like system that equips the low body to handle the upper body, distributing & absorbing our weight from the top down. They are key to how we feel.
SI joints, along with some award-winning strength provided by encasing ligaments, support our pelvis when walking, running + govern our gait. While strong, the encasing ligaments are not elastic. If over-stretched, they do not snap "back" like a rubber band. This means a one-time injury invites continuous vulnerability.
Deep hip muscles (like the psoas) also provide essential support & interplay with these structures. For example, if the SI joints lose structural integrity, the misalignment will task the surrounding muscles to work harder—and bear more of the upper body’s load.
The sciatic nerve also runs through this area (yay!) bearing the consequences of any dysfunction as well (pinched/trapped).
Too much/too little movement, hypermobility, female hormones—all interplay with SI joint (dys)function. Structurally, we are all different and ever-changing. Be mindful. Notice imbalance. For example, hamstring tightness on one side may translate to (destabilize) the ilium bones.
Health is adding a layer of intention to everything you do.
