What Is the SI Joint?
Your sacroiliac joints are situated in the lower back, where the sacrum and ilium converge. The triangle-shaped bone at the base of your spine, above your coccyx, or tailbone, is known as the sacrum. Your pelvis’ highest point is the ilium, one of the three bones that make up your hip bones.
Your body’s weight is supported by the SI joints, which distribute it evenly throughout your pelvis. They serve as a shock absorber and lessen the strain that movement places on your spine.
The SI joints’ bones are asymmetrical and fit together like a puzzle. The edges keep them in alignment. The SI joints’ muscles and extra-strong ligaments, which connect all of the bones, offer stability and restrict mobility. Even though it is only slight, this movement is essential for staying upright and even delivering birth.
The joint bones themselves are also lined with a protective layer of cartilage. The SI joints have fluid-filled spaces between their bones, which lubricates them. Free nerve endings are abundant in these areas, which enable them to communicate pain to the brain.
When the SI joint’s bones are misaligned or when the cartilage deteriorates and the bones start to contact, it can be very painful.