Sacroiliac Joint Dysfunction (SI Joint Pain)

SI join can be one of the lower back pain causes, even though its not really lower back muscles that are causing it.

The sacroiliac joint, or SI Joint, is the joint next to the bottom of the spine connecting the sacrum with the pelvis. Treatments for SI joint pain are usually non-surgical, and focus on the restoration of normal motion of the joint. SI joint irritation is a common cause of low back pain.

The joint typically has the following characteristics:

  • Small and very strong, reinforced by strong ligaments that surround it
  • Does not have much motion
  • Transmits all the forces of the upper body to the pelvis (hips) and legs
  • Acts as a shock-absorbing structure

While it is not clear how the pain is caused, it is thought that an alteration in the normal joint motion may be the culprit that causes sacroiliac pain. This source of pain can be caused by either:

  • Too much movement (hypermobility or instability): The pain is typically felt in the lower back and/or hip and may radiate into groin area.
  • Too little movement (hypomobility or fixation): The pain is typically felt on one side of the low back or buttocks, and can radiate down the leg. The sensation usually remains above the knee, but at times pain can extend to the ankle or foot. The pain is similar to sciatica, or pain that radiates down the sciatic nerve and is caused by aradiculopathy.

This condition is generally more common in young and middle-aged women.

Accurately diagnosing sacroiliac joint dysfunction can be difficult because the symptoms mimic other common conditions. Including other mechanical back pain conditions like facet syndrome as well as other lumbar spine conditions including disc herniation and radiculopathy (pain along the sciatic nerve that radiates down the leg).

Biomechanics of SI Joint

Since most SI joints only move about 2 to 4 millimeters during weight bearing and forward bending, they are described as a gliding-type joint. This motion is quite different from the hinge-type articulation at the knee or the ball-and-socket motion of the hip. Considered a viscoelastic joint, the SI’s major movement comes from ligamentous stretching. Therefore, its primary function within the pelvic girdle is to provide shock absorption for the spine by stretching in various directions. When sacroiliac joints work in perfect harmony with the third bony articulation of the pelvis (symphysis pubis). A marvelous self-locking mechanism develops that helps us walk. Aided by power GENERATED by the hip abductors (gluteus medius/ minimus, TFL and piriformis), the pelvic joints brace the weight-bearing side during gait. This locking system, termed force closure, allows smooth transference of body mass from one leg to the other.

Although no muscles directly bind down the three pelvic joints, when working synchronously with the SI ligaments they provide the pelvis − “the great adapter” − with a remarkable antigravity springing system that can absorb both ascending and descending forces.


During the aging process, there is an increase in the grooves on the opposing surfaces of the sacrum and ilium, which reduces available motion of the SI joint. This is a perfect example of the body’s innate wisdom attempting to sacrifice complexity of motion for stability. An interesting note is that the age with highest incidence of disabling back pain (25-45 years) is the same age at which the greatest amount of motion is available in the sacroiliac joints. It’s not uncommon for an SI joint to become stiff and permanently lock as we age. This may be a good reason for massage therapists to begin incorporating specialized soft-tissue mobilization techniques on a regular basis. To maintain joint-play and prevent agonizing arthrosis and arthritis from developing. Due to the small amount of sacroiliac movement and the joint’s inherent biomechanical complexity, proper assessment can be tricky.

Frequently, muscle imbalance patterns develop as tissues become strained from overuse, underuse or abuse. In the early stages of a typical SI pain episode, protective muscle spasm arises as the sacrum gets stuck side-bent and rotated between the ili. Usually from a forward-bending and twisting incident.

Sustained isometric contraction produces muscle toxicity and weakness causing increased SI ligament loading and overstretching. As the articulating joint surfaces become jarred loose, ligament microtearing creates an inflammatory response. Sensitive chemoreceptors bombard the spinal cord and brain with noxious stimuli, causing the brain to layer the area with protective muscle guarding. This is the beginning of a therapeutically challenging pain/spasm/pain CYCLE that often is hard to break. It’s possible, however, to eliminate pain emanating from hypermobile joints by restoring proper pelvic alignment. Frictioning the loose ligaments and addressing core strengthening exercises.

Best Stretches for SI Joint:

See more of the stretches for the lower back in this video I’ve made as well while in my office:

Activities that can make SI Joint Pain worse:

There are certain exercises that aggravate the sacroiliac joint by putting extra pressure on the SI joints.








-Jolita Brilliant, Licensed Massage Therapist in Burlington, Vermont


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