When people talk about “low back pain,” they usually point to the lumbar spine. But in a PT clinic, we often find the true culprit lies just below: the sacrum. Understanding this triangular bone can change the way we approach back pain, recovery, and long-term movement health.
What is the Sacrum?
The sacrum is a wedge-shaped bone at the base of your spine, nestled between the two halves of your pelvis. It connects the lumbar vertebrae above with the coccyx (tailbone) below and forms the back portion of the pelvis. On each side, it meets the iliac bones at the sacroiliac (SI) joints.
Think of it as a keystone in an arch: the sacrum locks the pelvis together, allowing for stability while also transmitting forces between the upper body and the legs.
Why the Sacrum Matters in Low Back Pain
-
Force Transfer
Every time you walk, lift, or twist, forces travel through the sacrum. If this bone or its surrounding joints aren’t moving well, or if they’re moving too much, your low back may be forced to compensate. -
Sacroiliac Joint Dysfunction
The SI joints are small, but they play a big role. Too much stiffness or too much mobility can both cause pain. Often, people mistake SI joint pain for lumbar spine pain, since it radiates to the same regions. -
Muscle Attachments
The sacrum anchors several key muscles: the gluteus maximus, piriformis, and parts of the pelvic floor. If these muscles are weak, tight, or imbalanced, they can pull unevenly on the sacrum, contributing to discomfort in the low back. -
Posture and Alignment
Subtle shifts in sacral tilt, such as from prolonged sitting, pregnancy, or trauma, can alter how the spine stacks above. Even a few degrees of change can lead to pain and compensatory patterns in the lumbar region.
How Physical Therapy Addresses Sacral-Related Pain
-
Movement Assessment: We look for asymmetry, stiffness, or excessive motion in the SI joints and surrounding muscles.
-
Manual Therapy: Gentle mobilization or soft tissue work can help restore normal motion.
-
Stability Training: Strengthening the core, glutes, and pelvic stabilizers helps the sacrum stay balanced and supported.
-
Stretching and Mobility Work: Tight hips and hamstrings often overload the sacrum, addressing this reduces strain on the low back.
-
Education: Teaching patients about posture, lifting mechanics, and daily habits ensures long-term protection of the sacrum and lumbar spine.
The Takeaway
Low back pain isn’t always just a “back problem.” The sacrum is a central hub that links your spine, pelvis, and legs. When it’s not moving well, or when the surrounding muscles aren’t supporting it properly, the whole system feels the strain.
By addressing the sacrum’s role, physical therapy provides a more complete path to healing and long-term resilience.
Looking to optimize your well being with pelvic floor physical therapy? Reach out to us at Pelvic Health Center in Madison, NJ to set up an evaluation and treatment! Feel free to call us at 908-443-9880 or email us at [email protected].