﻿ Sacroiliac Joint Dysfunction (SI Joint Pain) Causes, Symptoms, Diagnosis, Treatment, and Prevention - MedicineNet

Sacroiliac Joint Dysfunction
(SI Joint Pain)

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What are the sacroiliac (SI) joints?

The sacroiliac (SI) joints are formed by the connection of the sacrum and the right and left iliac bones. The sacrum is the triangular-shaped bone in the lower portion of the spine, below the lumbar spine. While most of the bones (vertebrae) of the spine are mobile, the sacrum is made up of five vertebrae that are fused together and do not move. The iliac bones are the two large bones that make up the pelvis. As a result, the SI joints connect the spine to the pelvis. The sacrum and the iliac bones (ileum) are held together by a collection of strong ligaments. There is relatively little motion at the SI joints. There are normally less than 4 degrees of rotation and 2 mm of translation at these joints. Most of the motion in the area of the pelvis occurs either at the hips or the lumbar spine. These joints do need to support the entire weight of the upper body when we are erect, which places a large amount of stress across them. This can lead to wearing of the cartilage of the SI joints and arthritis.

What is sacroiliac joint dysfunction?

There are many different terms for sacroiliac joint problems, including SI joint dysfunction, SI joint syndrome, SI joint strain, and SI joint inflammation. Each of these terms refers to a condition that causes pain in the SI joints from a variety of causes.

What are the causes of sacroiliac joint dysfunction?

As with most other joints in the body, the SI joints have a cartilage layer covering the bone. The cartilage allows for some movement and acts as a shock absorber between the bones. When this cartilage is damaged or worn away, the bones begin to rub on each other, and degenerative arthritis (osteoarthritis) occurs. This is the most common cause of SI joint dysfunction. Degenerative arthritis occurs commonly in the SI joints, just like other weight-bearing joints of the body.



There are many disorders that affect the joints of the body that can also cause inflammation in the SI joints. These include gout, rheumatoid arthritis, psoriasis, and ankylosing spondylitis. These are all various forms of arthritis that can affect all joints. Ankylosing spondylitis is an inflammatory arthritis that always affects the SI joints. It can lead to stiffness and severe pain in the SI joints. As the disease process continues, the SI joints fuse together and have no further motion. Once this occurs, there is no further pain associated with the SI joints.

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Sacroiliac Joint Pain (SI Joint Pain) Symptoms

The most common symptom of SI joint dysfunction is pain. Patients often experience or the back of the hips. Pain may also be present in the groin and thighs. In many cases, it can be difficult to determine the exact source of the pain. Your physician can perform specific tests to help isolate the source of the pain. The pain is typically worse with standing and walking and improved when lying down. Inflammation and arthritis in the SI joint can also cause stiffness and a burning sensation in the pelvis.

