Sacroiliac Joint pain (SI joint) accounts for over 30% of all low back pain. SI joint pain can affect both males and females. If you specifically have pain off to the side of your spine, or even over the “dimples” in your lower back, that is a good indicator that you have an SI issue.
The SI joint is made up of 2 main bony structures: the sacrum and inominate. The sacrum is comprised of the last 5 vertebral segments fusing together to form one bone that extends all the way to your tail bone (coccyx). The inominate is essentially your hip bone. It is actually a combination of 3 bones, the ilium, ischium and pubis. We will mostly focus on the ilium, which is what directly articulates (joins) with the sacrum.
How can my SI joint be affected? Different daily activities can affect your body in many different ways. Let’s begin with the basics; the area we are speaking of is a joint, meaning it is comprised of two surfaces that can move, roll, glide on one another. Keeping those joints stable is a series of ligaments. Ligaments are the connective tissues in the body that connect bone to bone. Ligaments have elastic properties that allow them to stretch and recoil with activities. However, if you overstretch the elastic past its limit, it is much harder for it to recoil and will remain overstretched. This overstretch can cause increased pain and hypersensitivity in the area affected.
SI joint pain can affect both sexes, although females are more affected than men. Why are women more affected than men? Women have smaller, rounder, smoother joint surfaces, which allows for increased movement. Women have hormonal differences that make their ligaments more “lax”, flexible. Due to the increased width of their pelvis’, women carry themselves in a different line of gravity, creating more torque (or rotational force) distributed through their lower back, pelvis and hips. All of these unique features allow the female the ability to carry and birth a child. With all these unique features, in addition to the stresses on ligaments caused by sexual intercourse positions and childbirth, the female pelvis is more at risk for an SI strain than males.
Anyone can make themselves prone to an SI strain. Single legged standing, a dramatic fall on your buttocks, sexual intercourse positions, forceful golf swings, motor vehicle accidents, and other traumatic injuries involving high forces are all prime examples of a possible SI strain misdiagnosed as low back pain. Because the SI joint is comprised of two bony structures it has the ability to rotate, shift, and slide. Common SI joint instabilities involve one or more of the adjoining surfaces to rotate anteriorly (tilt forward) or posteriorly (tilt backward). In addition, the joint can move laterally (outward), medially (inward) or into more flexion (forward) and extension (backward). An instable joint with overstretched ligaments can cause a feeling of instability and increased pressure in the lower hip, buttocks region.
How do you know if it is SI pain vs low back pain? Sure, it can absolutely be a little of both. Most SI strains/instabilities are co-managed with a series of core/trunk/back endurance training exercises to strengthen the muscles that connect the pelvis to the low back and legs.
To treat the SI joint, see a Physical Therapist or rehabilitation professional that can examine and interpret findings to identify impairments to see if indeed your pain is coming from the sacroiliac joint. If the ligaments supporting the joint are strained/lax/unstable, an SI belt might be indicated. The SI belt is an elastic band that wraps around the ASIS (anterior superior iliac spine), or just below your belt line, to compress the ligaments in question so they have adequate time and support to stabilize and heal. Exercises are also prescribed to lengthen, strengthen, and reinforce muscles that surround the SI joint.