If you feel pain near your tailbone when you sit, is it your SI joint?

Pain low on one side of your back, near the dimple above your buttock, that flares when you sit, stand up, or climb stairs can point to the sacroiliac joint. This joint, often called the SI joint, connects the base of your spine to your pelvis and can become a source of pain when it is irritated.

If you feel the pain mostly on one side and can nearly point to it with a finger, that localized pattern is common with SI joint problems. The pain may spread into the buttock or upper thigh, but it usually does not travel far down the leg the way nerve pain does.

If you feel worse after sitting for a long time, rolling over in bed, or standing from a chair, those everyday movements loading the joint are typical triggers. Some people also feel it more on one leg when going up stairs.

Other conditions can mimic this, including hip problems and lower spine issues, which is why an exam comes first. An SI joint injection can both reduce inflammation and help confirm the joint as the source based on the relief you feel.

The injection places anti inflammatory medicine into or near the joint using imaging for accuracy. If you feel clear relief afterward, that supports the SI joint as the cause.

If you feel your pain matches this pattern, describe exactly where it sits and what movements set it off. Those specifics help your specialist tell the SI joint apart from the hip or spine and decide whether an injection is the right next step for you.

This is general information, not medical advice. Whether a treatment is right for you is determined by a physician after an evaluation.