Sacroiliac Joint Dysfunction: Why Your SI Joint May Be Causing Pain

Pain in the lower back or buttocks is often attributed to muscles, discs, or the spine. However, another structure can be responsible: the sacroiliac (SI) joint. The SI joints connect the sacrum at the base of the spine with the pelvis and help transfer forces between the upper body and legs.

When an SI joint becomes irritated or does not move normally, it can cause pain that may be difficult to distinguish from other sources of low back pain. Understanding the symptoms, causes, diagnosis, and treatment options for sacroiliac joint dysfunction can help patients determine when professional evaluation may be appropriate.

What Is Sacroiliac Joint Dysfunction?

Sacroiliac joint dysfunction is a condition in which one or both SI joints become painful because of irritation, inflammation, altered movement, or mechanical stress. The SI joints are designed to provide stability rather than extensive movement, but they still move slightly as the body bends, walks, and changes position.

When the joint or surrounding structures become irritated, pain can develop around the lower back, buttocks, pelvis, or sometimes the upper leg. Because several conditions can produce similar symptoms, identifying the SI joint as the actual pain generator can require a careful evaluation.

Where Does SI Joint Pain Usually Occur?

SI joint pain usually occurs in the lower back or buttock on one side, although some people experience symptoms on both sides. Pain may also extend into the hip, groin, thigh, or upper leg.

Unlike certain nerve-related conditions, SI joint pain does not typically follow a consistent nerve pathway. Symptoms may become worse with prolonged sitting or standing, climbing stairs, turning in bed, running, or transitioning from sitting to standing. Some patients describe the discomfort as aching, sharp, or pressure-like.

What Causes Sacroiliac Joint Dysfunction?

Sacroiliac joint dysfunction can have several possible causes. Repetitive stress, changes in walking mechanics, injuries, arthritis, and differences in how forces are distributed through the pelvis can contribute to SI joint irritation.

Pregnancy can also affect the SI joints because hormonal and biomechanical changes alter pelvic stability. Previous injuries involving the lower back, pelvis, or legs may change movement patterns and place additional stress on the joint. In some cases, the precise cause cannot be identified, but the SI joint can still be confirmed as a source of pain.

How Can SI Joint Dysfunction Be Different From Other Causes of Back Pain?

SI joint dysfunction can resemble several other conditions, including lumbar disc problems, spinal stenosis, hip disorders, and muscle-related pain. This overlap is one reason SI joint pain can be challenging to diagnose based on symptoms alone.

Pain that is primarily located below the belt line and toward one side of the buttock may raise suspicion of SI joint involvement, particularly when certain movements reproduce the symptoms. However, location alone is not enough to establish a diagnosis. A clinician may use a combination of medical history, physical examination, and diagnostic testing.

How Is Sacroiliac Joint Dysfunction Diagnosed?

Sacroiliac joint dysfunction is diagnosed through a combination of clinical findings rather than a single test. During an evaluation, a physician may examine the spine, hips, pelvis, and surrounding muscles while performing specific maneuvers designed to stress the SI joint.

Imaging such as X-rays, MRI, or CT scans may be used to evaluate other potential causes of pain or identify structural changes. However, imaging does not always show whether the SI joint is responsible for a patient’s symptoms.

In selected patients, a diagnostic SI joint injection may provide additional information. A small amount of local anesthetic is delivered into the joint under image guidance. Significant temporary pain relief after the injection can support the diagnosis that the SI joint is contributing to the patient’s pain.

What Treatments Are Available for SI Joint Pain?

Treatment for SI joint dysfunction depends on the underlying cause, severity of symptoms, and patient’s overall health. Conservative care may include physical therapy, activity modification, targeted exercises, and other measures designed to improve strength, flexibility, and pelvic stability.

When symptoms persist despite conservative treatment, interventional pain management may provide additional options. An image-guided SI joint injection can sometimes be used for both diagnostic and therapeutic purposes. In some cases, radiofrequency ablation may be considered to reduce pain signals from nerves associated with the SI joint.

The appropriate treatment should be based on an individualized evaluation rather than assuming that every patient with buttock or lower back pain has the same condition.

Can Physical Therapy Help SI Joint Dysfunction?

Physical therapy can help SI joint dysfunction by addressing factors that may contribute to abnormal stress around the pelvis and lower back. A physical therapist may develop exercises that strengthen the core, gluteal muscles, and other structures that support pelvic stability.

Physical therapy may also address movement patterns, flexibility, posture, and functional activities. For some patients, these strategies can reduce strain on the SI joint and improve the ability to perform everyday activities.

When Should You See a Doctor for SI Joint Pain?

Patients should consider medical evaluation when lower back, buttock, or pelvic pain persists, repeatedly returns, interferes with normal activities, or does not improve with appropriate self-care. Evaluation is particularly important when the source of pain is uncertain because several spinal, hip, and pelvic conditions can produce similar symptoms.

Sudden severe pain following an injury, new weakness or numbness, loss of bladder or bowel control, fever, or other concerning symptoms warrant prompt medical attention.

Can SI Joint Dysfunction Become a Chronic Pain Problem?

SI joint dysfunction can become a chronic pain problem when irritation persists or contributing mechanical factors are not addressed. Chronic SI joint pain may affect walking, exercise, sleep, work, and other daily activities.

A comprehensive pain management approach can help identify the source of symptoms and determine whether physical therapy, medication, injections, radiofrequency procedures, or other treatments may be appropriate. The goal is not simply to reduce pain temporarily but to improve function and address factors that may contribute to recurring symptoms.

What Should Patients Know About SI Joint Pain?

Sacroiliac joint dysfunction can be an overlooked cause of lower back and buttock pain. Because its symptoms overlap with many other musculoskeletal and spinal conditions, an accurate diagnosis is important before treatment begins.

Patients experiencing persistent pain around the lower back, pelvis, or buttocks should not assume that the spine is always responsible. A medical evaluation can help determine whether the SI joint, spine, hip, or another structure is contributing to symptoms and guide an appropriate treatment plan.