FAQs

Sacroiliac Joint

Disc vs. Sacroiliac Joint

Prior to 1934, when lumbar disc herniation was discovered, the sacroiliac joint was thought to be the major source of low back pain. About that time, concern was diverted to surgical remedies for discs which, although providing dramatic relief in some cases, have proven to be limited in relieving many low back complaints.  With the recent emergence of biomechanical science, the sacroiliac joints are again considered to play a pivotal role in the total musculoskeletal complex.

What is the Sacroiliac Joint and how does it work?
The sacroiliac joints are two of the most important support centers of the body, positioned where the body’s weight transfers from the spine obliquely through the pelvis to the legs. Studies conclude that the sacroiliac joints are important sensors of large force streams between the trunk and legs in which the largest muscles of the body are involved. In this respect, the sacroiliac joint functions as a multi-directional force transducer. The base of the spinal column, the sacrum, is supported at its attachment to the iliac bones of the pelvis solely by strong ligaments that make up the sacroiliac joints. Within these ligaments are nerves which control and orient the body’s posture. Sprain of these ligaments caused instability (looseness) which leads to muscle spasm, pain, and postural imbalances throughout the body.
Can a SIJ injury cause sciatica pain?
Yes, as a matter of fact, muscular adaptations to SIJ injury are the main cause of sciatic pain for two reasons, which are both related to compression of the sciatic nerve. In combination, the pelvic muscles alter the structural balance, causing narrowing of the nerve root opening, which puts pressure on the sciatic nerve roots as they exit the spine. The piriformis is one particular muscle that plays a more direct role in protecting an injured SIJ. The sciatic nerve runs either through, or just below this muscle so that, when tight to protect the SIJ, the piriformis can compress the sciatic nerve.