What is the sacral spine?

​

The sacrum is a triangle-shaped bone that connects to your hips. It consists of five sacral vertebra (S1-S5) that fuse together in utero, so they do not move. Together with the hip bones, the sacrum forms the ring called the pelvic girdle.

​

Below the sacrum is the coccyx, or the tailbone. These four fused vertebrae make up the bottom of your spine. The coccyx attaches to pelvic floor muscles and ligaments.

​

What are common causes of sacral pain?

​

Sacroiliitis is painful inflammation in the joints where your spine connects to your pelvis (your sacroiliac (SI) joints). It causes pain in the lower back, butt, or legs.

​

A joint is a place in the body where two bones meet. The sacroiliac joints are the connection between the spine and pelvis. Specifically, they’re the place where the sacrum (the triangle-shaped last section of your spine) meets the ilium (the top part of your pelvis).

​

The sacroiliac joints are some of the biggest joints in the body, and they are used every time the hips move or shift. Sacroiliitis happens when something irritates or damages one or both of the sacroiliac joints. This irritation leads to inflammation, which causes pain that will usually be felt in the low back and butt.

​

What are sacroiliitis symptoms?

​

Pain in the lower back is the most common sacroiliitis symptom. The pain might:

​

• Get worse after sitting or standing in one position for a long time

• Get worse with turning or rotating the hips

• Feel suddenly sharp and stabbing, or may be a dull ache

• Radiate from the low back into your butt, hips or thighs

​

People with sacroiliitis often feel stiff first thing in the morning. It’s common to have some stiffness after sleeping or sitting in one position, but the stiffness sacroiliitis causes usually lasts for more than an hour every morning.

​

What causes sacroiliitis?

​

Anything that causes inflammation in your joints can affect the sacroiliac joints and cause sacroiliitis. Arthritis is the main cause of sacroiliitis, including:

​

• Ankylosing spondylitis

• Psoriatic arthritis

 

Other health conditions that cause inflammation can cause sacroiliitis too, including:

​

• Crohn’s disease

• Ulcerative colitis

• Reactive arthritis (Reiter’s syndrome)

• Behçet’s disease

​​

Women sometimes experience sacroiliitis during pregnancy. The hormones, specifically relaxin, that allows the hips to open and the joints to relax during pregnancy can make the sacroiliac joints widen and rotate.

​

A rare bacterial infection (Staphylococcus aureus) can cause sacroiliitis if the infection attacks the sacroiliac joints.

​

How is sacroiliitis treated?

​

Physical therapy is the most common treatment for sacroiliitis. A physical therapist provides stretches and exercises to strengthen the muscles around the sacroiliac joints. This will take pressure off the joints and promotes greater stablility. However, more research is being done that shows sacroiliitis, especially after pregnancy, is a result of pelvic floor instability after childbirth and research is showing improvement in sacroiliitis after pelvic floor physical therapy. Doing exercises for sacroiliitis will also help to increase the range of motion in the sacroiliac joints.

 

Pain due to sacroiliitis can be treated with medications, including:

​

• NSAIDs

• Muscle relaxers

• Corticosteroids

 

Sacroiliitis surgery

​

It’s rare to need surgery for sacroiliitis. Surgery may be considered if physical therapy and other treatments haven’t improved the pain.

​

Surgery would consist of a sacroiliac joint fusion, which permanently fastens the joint together with surgical screws.