The sacroiliac joints (SIJ) are located at the base of the spine and are the joints connecting the sacrum (base of the spine) to the pelvis. A sprain refers to an injury of a ligament where an external force causes overstretching and possible tearing of the ligament fibres. There are various types of SIJ sprains ranging from mild to severe.
- A mild sprain is typically associated with prolonged sitting or stretching the wrong way and presents as mild pain over the SIJ region.
- Moderate SIJ sprains are often the result of an untreated mild sprain, where the joint instability has continued. They present as moderate pain over the SIJ region, made worse by sitting for more than 30 minutes.
- Severe SIJ sprains are either due an unresolved moderate sprain or from significant trauma to the SIJ ligaments. They present as pain over the SIJ region which may radiate down into the lower back, down into one or both thighs, hips and/or groin region. Severe sprains may also lead to lumbar disc problems due to the instability of the iliolumbar ligaments which connect the SIJ to the lumbar vertebra.