The sacroiliac joint (SIJ) is a term used to describe the place where the sacrum and the iliac bones join.
- The sacrum is located at the base of your spine. It is made up of 5 vertebrae, or backbones, that are fused together.
- The iliac bones are the two large bones that make up your pelvis. The sacrum sits in the middle of the iliac bones.
More About Your Problem
The main purpose of the SIJ is to connect the spine and the pelvis. As a result, there is very little movement at this joint.
Major reasons for pain around the SIJ include:
- Pregnancy. The pelvis widens to prepare for birth, stretching the ligaments (strong, flexible tissue that connects bone to bone).
- Different types of arthritis.
- Difference in leg lengths.
- Wearing away of the cartilage (cushion) between the bones.
- Trauma from impact, such as landing hard on the buttocks.
- History of pelvic fractures or injuries.
- Muscle tightness.
Although SIJ pain can be caused by trauma, this type of injury more often develops over a long period.
What to Expect
Symptoms of SIJ dysfunction include:
- Pain in the lower back, usually only on one side
- Hip pain
- Discomfort with bending over or standing after sitting for long periods
- Improvement in pain when lying down
To help diagnose an SIJ problem, your health care provider may move your legs and hips around in different positions. You may also need to have x-rays or a CT scan. Your provider may want you to have an injection to the SIJ to accurately locate your pain.
Your provider may recommend these steps for the first few days or weeks after your injury or when starting treatment for SIJ pain:
- Rest. Keep activity to a minimum and stop movements or activity that worsen the pain.
- Ice your lower back or upper buttocks for about 20 minutes 2 to 3 times a day. Do not apply ice directly to the skin.
- Use a heating pad on the low setting to help loosen tight muscles and relieve soreness.
- Massage the muscles in the lower back, buttocks, and thigh.
- Take pain medicines as instructed.
For pain, you can use ibuprofen (Advil, Motrin), naproxen (Aleve, Naprosyn), or acetaminophen (Tylenol). You can buy these medicines at the store without a prescription.
- Talk with your provider before using these medicines if you have heart disease, high blood pressure, kidney disease, or have had stomach ulcers or internal bleeding in the past.
- Do not take more than the amount recommended on the bottle or by your provider.
If this is a chronic problem, your provider may prescribe an injection to help with pain and inflammation. The injection can be repeated over time if needed.
Keep activity to a minimum. The more time the injury has rest, the better. For support during activity, you can use a sacroiliac belt or lumbar brace.
Physical therapy is an important part of the healing process. It will help relieve pain and increase strength. Talk to your doctor or physical therapist for exercises to practice.
Here is an example of an exercise for your lower back:
- Lie flat on your back with your knees bent and feet flat on the ground.
- Slowly, begin to rotate your knees to the right side of your body. Stop when you feel pain or discomfort.
- Slowly rotate back toward the left side of your body until you feel pain.
- Rest in the starting position.
- Repeat 10 times.
The best way to get rid of SIJ pain is to stick to a care plan. The more you rest, ice, and do exercises, the quicker your symptoms will improve or your injury will heal.
Your provider may need to follow up if the pain is not going away as expected. You may need:
- X-rays or imaging tests such as a CT or MRI
- Blood tests to help diagnose the cause
When to Call the Doctor
Call your provider if you have any of the following:
- Sudden numbness or tingling in your lower back and hips
- Weakness or numbness in your legs
- Have problems controlling of your bowel or bladder
- Sudden increase in pain or discomfort
- Slower than expected healing
- Sudden increase in pain in your other joints and pain in your eyes and when passing urine
SIJ pain - aftercare; SIJ dysfunction - aftercare; SIJ strain - aftercare; SIJ subluxation - aftercare; SIJ syndrome - aftercare; SI joint - aftercare
Cohen SP, Chen Y, Neufeld NJ. Sacroiliac joint pain: a comprehensive review of epidemiology, diagnosis and treatment. Expert Rev Neurother. 2013;13(1):99-116. PMID: 23253394 pubmed.ncbi.nlm.nih.gov/23253394/.
Isaac Z, Brassil ME. Sacroiliac joint dysfunction. In: Frontera WR, Silver JK, Rizzo TD, eds. Essentials of Physical Medicine and Rehabilitation. 4th ed. Philadelphia, PA: Elsevier; 2019:chap 51.
Placide R, Mazanec DJ. Masqueraders of spinal pathology. In: Steinmetz MP, Benzel EC, eds. Benzel's Spine Surgery. 4th ed. Philadelphia, PA: Elsevier; 2017:chap 26.
Review Date 11/12/2020
Updated by: C. Benjamin Ma, MD, Professor, Chief, Sports Medicine and Shoulder Service, UCSF Department of Orthopaedic Surgery, San Francisco, CA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.