Sacroiliac Joint (SI Joint)
What is the Sacroiliac Joint (SI Joint)?
The Sacroiliac Joint (SI Joint) is located at where the spine joins the hips to become part of the Pelvic Girdle. The Spine is composed of 33 bones that are divided into 4 sections: Cervical, Thoracic, Lumbar, and Sacral. The Pelvic girdle, or as we often refer to as the hips, is composed multiple bones fused together: Sacrum, Ilium, Ischium, Acetabulum, and Pubis.
Sacroiliac Joint (SI Joint) skeletal anatomy
Sacrum – the lowest portion of the spine. There is no spinal cord running through this portion, only nerves, and the bones have naturally fused together. This series of fused bones connects to the two bilateral Ilium bones with a small, but cartilage lined joint called the Sacroiliac joint (SI joint).
Ilium – The two Ilium bones are the most pronounced upper bones in the hips. If you run your hands over the hips you will feel two boney protrusions along the front topside of your hips. These boney protrusions are the top ridge of the Ilium Bones and are called the Iliac Crest. The Ilium bones fuse with the lower bone called the ischium and form a joint with the sacrum called the Sacroiliac Joint.
Ischium – The two lowest bones in the hip. The Ischium first fuses with the pubic bone and then later with the acetabulum and Ilium.
Acetabulum – the hip socket in which the leg connects to the hips.
Pubis – the front central bone that connects the two sides of the hips in the front by the genitals. The pubis sits underneath the pubic mound.
What is Sacroiliac Joint (SI Joint) Dysfunction?
The Sacroiliac Joint (SI Joint) is a common source of lower back pain and estimated to be the culprit is up to a third of all lower back pain cases. To the average person the pain can seem very similar to sciatica or a ruptured lumbar disc as the pain can potentially radiate down the legs. This pain could be a early indicator of Ankylosing Spondylitis (Bechterew’s disease). The pain is usually localized to the lower back and get worse while side sleeping or during pregnancy. The pain is often a dull aching pain, but can also have sharp stabbing moments, that is present in the lower back, buttocks, and groin and can spread to the upper back of thighs, but rarely going below the knees The Sacroiliac joint can become irritated and lead to stiffness or a feeling of instability, and the pain is often worse while using the joint to exercise.
Treatment for Sacroiliac Joint (SI Joint) Dysfunction
Treatment for the Sacroiliac (SI) Joint is often a multi-modal approach that can utilize oral, and injections of corticosteroids, lifestyle modification, and a solid physical therapy routine to be completed at home and in person under the guidance of a physical therapist or chiropractor.
Sacroiliac Joint (SI Joint) Injection
A Sacroiliac Joint (SI Joint) Injection is a minor procedure, similar to a epidural steroid injection, where the joint is injected under fluoroscopic guidance with a combination of anesthetic and corticosteroid. A fluoroscope is used for the doctor to be able to watch the injection in real time on X-ray video to ensure proper placement of the drug cocktail. The anesthetic will offer immediate relief to the joint if the joint is the issue, confirming the diagnosis, and the corticosteroid will offer short term to medium term relief of the symptoms.
Physical Therapy can be utilized to increase flexibility of the Sacroiliac (SI) Joint and strengthen the surrounding tissues. The goal of physical therapy is to have full range of motion of the hip and to develop a proper angle of pelvic tilt so that the Sacroiliac (SI) Joint will no longer be irritated.
The Sacroiliac (SI) Joint can become arthritic beyond the scope of healing by conservative treatments. In these rare cases considering a fusion of the Sacrum to the Ilium by a Spine Surgeon may be worth looking into if pain management is no longer an option. The fusion of a critical joint for movement should never be taken lightly, so it is important to fully understand what quality of life changes are to be expected after -recovery.