Common possibilities
- Mechanical SI-joint dysfunction
- Arthritic or inflammatory change
- Pregnancy/postural or biomechanical stress
- Trauma or repetitive loading
- Pain referred from the lumbar spine or hip
NEXUS PAIN EDUCATION
Sacroiliac (SI) Region Pain
Understand the anatomy, possible causes, warning signs, and the kinds of evaluation and treatment approaches that may be considered.
Sacroiliac / Lumbosacral Region — interactive 3DDrag/rotate and zoom inside the NIH 3D viewer when supported.
Region-specific educational anatomy. Open the NIH 3D model in a new tab if the embedded viewer is unavailable. This model is for education and does not diagnose the cause of pain.
ANATOMY
Structures involved
Sacroiliac joints, sacrum, pelvis, gluteal muscles, ligaments and nearby lumbar structures.
Symptoms can arise from more than one structure. Location alone cannot reliably identify the cause, so history and examination matter.
COMMON POSSIBILITIES
What may contribute to sacroiliac (si) region pain?
Why symptoms vary
Pain intensity does not always match the amount of structural change seen on imaging. A clinical evaluation considers function, neurologic findings, medical history, and symptom pattern.
Not every case needs imaging
Imaging and diagnostic testing are selected when the history, examination, persistence of symptoms, trauma, neurologic findings, or other clinical factors make them useful.
SYMPTOMS
What patients may notice
- Pain near one or both buttocks
- Pain with prolonged standing or transitions
- Pain that may extend into the thigh
- Tenderness near the SI region
- Symptoms that overlap with hip or lumbar pain
How Nexus may evaluate pain
An evaluation may include symptom history, medication review, functional limitations, physical examination, neurologic assessment when relevant, review of prior records or imaging, and additional testing or referral when clinically indicated.
No medication, injection, imaging study, controlled substance, procedure, or referral is guaranteed.
TREATMENT APPROACHES
Care is matched to the diagnosis and patient.
Conservative care
- Activity modification while avoiding prolonged bed rest
- Clinically appropriate medications
- Physical therapy, mobility and strengthening
- Diagnostic testing when indicated
- Selected injections or specialist referral when appropriate
- Surgery only for selected conditions after evaluation
Medication safety
Medication choices depend on diagnosis, other medical conditions, current medicines, risks, benefits, prior treatment response, and applicable prescribing requirements.
Procedures & referrals
Selected patients may benefit from procedural evaluation or referral to physical therapy, imaging, orthopedics, neurology, spine care, rheumatology, or another specialty depending on findings.
Seek urgent or emergency evaluation when appropriate
Severe symptoms after major trauma, new bowel or bladder dysfunction, new or progressive weakness, fever with severe pain, a hot/red swollen joint, inability to bear weight after injury, chest pain, trouble breathing, or other rapidly worsening symptoms can require urgent assessment. Call 911 for an emergency.
Patient education only. This page does not establish a physician-patient relationship, diagnose the cause of pain, or provide an individualized treatment plan.