The sacroiliac joints, more commonly called the SI joints, sit where the base of your spine meets your pelvis. You have one on each side, and their job is to transfer the weight of your upper body down through your hips and legs. They are built for stability, not for a wide range of motion, and they rely on a complex system of ligaments, muscles, and cartilage to stay in balance.
SI joint dysfunction is a broad term used to describe pain that originates from or around one or both of these joints. It is one of the more underrecognized sources of lower back and pelvic pain, partly because its symptoms can look a lot like other conditions, such as a herniated disc or hip problems.
The pain can range from mild and nagging to sharp and disabling, and it often affects everyday activities like walking, standing, climbing stairs, or even sitting for long periods. Understanding what SI joint dysfunction is, how it develops, and what makes it different from other types of pain is an important first step toward getting the right kind of help.
Because SI joint dysfunction can be influenced by posture, movement patterns, injury, instability, and surrounding muscle imbalance, treatment often works best when it is tailored to the source and pattern of your symptoms. At The Accident Doctor, we offer conservative care options designed to help reduce pain, improve mobility, and support better pelvic and lower back function.
Depending on your needs, your treatment plan may include Chiropractic Care, Physical Rehabilitation, and Massage Therapy. We also provide focused injury-related care through Auto Accident Care, Sports Injury Care, and Work Injury Care.
If SI joint-related pain is affecting your ability to sit, stand, walk, sleep, or move comfortably through your daily routine, our team can help you explore care options tailored to your symptoms and goals.
SI joint dysfunction can develop in several different ways, and the underlying cause often shapes how the condition behaves and where symptoms appear.
One of the most common causes is mechanical stress, meaning the joint has been placed under forces it was not designed to handle. This can happen gradually over time through poor posture, repetitive one-sided movements, or uneven loading of the pelvis. It can also happen suddenly as a result of a fall, a car accident, or other trauma that directly affects the pelvis or lower back.
Pregnancy is another well-known cause. During pregnancy, the body releases hormones that relax the ligaments supporting the pelvis in preparation for childbirth. This increased flexibility can make the SI joints less stable, leading to pain that may persist after delivery.
Degenerative changes can also affect the SI joint, just as they can affect other joints in the body. Over time, the cartilage that cushions the joint surfaces may wear down, leading to discomfort, stiffness, and inflammation.
In some cases, SI joint pain is linked to inflammatory conditions that affect the spine and pelvis more broadly. These types of inflammatory changes are different from mechanical dysfunction and typically involve the immune system, making them part of a separate category of diagnosis and care.
Other contributing factors can include leg length differences, previous spinal surgeries that change how load is distributed through the pelvis, and muscle imbalances that affect how the joint is supported during movement.
SI joint dysfunction most commonly causes pain in the lower back, buttock, or hip on one side of the body, though both sides can be affected. The pain is often described as a dull, aching sensation that may flare up with certain movements or positions.
Common symptoms include:
One helpful clue that points toward SI joint involvement is where the pain is located. Many people with SI joint dysfunction can point to a specific spot just below and to the inside of the dimple on the lower back, roughly over the SI joint itself.
It is worth noting that SI joint symptoms can also travel down the leg, which sometimes leads people to assume the problem is a nerve issue. Unlike true nerve pain, however, SI joint-related leg discomfort typically does not follow a clear nerve pathway and is usually felt more in the back of the thigh than below the knee.
While anyone can develop SI joint dysfunction, certain factors can increase the likelihood of experiencing it.
Women are more commonly affected than men, largely because of differences in pelvic anatomy and the physical changes that accompany pregnancy and childbirth. The wider, shallower shape of the female pelvis places different mechanical demands on the SI joints, and hormonal changes during pregnancy can reduce joint stability.
People who spend long hours sitting, especially in positions that place uneven pressure on the pelvis, may be more vulnerable over time. Similarly, those whose work or daily routines involve repetitive one-sided activity, heavy lifting, or prolonged standing can experience cumulative stress on the joint.
A history of lower back or pelvic injury is another relevant factor. When an injury disrupts the normal mechanics of the pelvis or spine, the SI joints may take on extra load as a result. This is also one reason why SI joint problems are sometimes seen following spinal surgery.
Age plays a role as well. Like other joints, the SI joint can undergo degenerative changes with age, which may reduce its ability to absorb and distribute load as effectively as it once did.
Certain inflammatory conditions that affect the spine and sacroiliac joints can occur in younger adults and may present differently than mechanical SI joint pain, with stiffness that is often worse in the morning and improves with movement.
This is a question that comes up often, and it is a completely understandable one since both conditions can cause pain in the lower back and buttocks that sometimes travels down the leg.
Sciatica refers to pain caused by irritation or compression of the sciatic nerve, which runs from the lower back through the buttocks and down the leg. True sciatic pain typically travels in a distinct pattern along the back of the leg, often reaching past the knee and sometimes into the foot. It may be accompanied by numbness, tingling, or weakness in the leg.
SI joint dysfunction, on the other hand, is not caused by a compressed nerve. The pain comes from the joint and its surrounding tissues, not from nerve irritation. While SI joint pain can radiate into the buttock, hip, groin, or upper thigh, it usually does not travel as far down the leg as sciatic pain, and it typically does not cause the same kind of numbness or tingling in the foot.
The two conditions can sometimes coexist, which is part of what makes accurate diagnosis so important. Getting to the correct source of pain is key to understanding what is happening in your body and deciding what steps to take next.
There are several widespread misconceptions about SI joint dysfunction that can make it harder for people to understand what they are experiencing.
Myth: If your X-ray or MRI looks normal, nothing is wrong.
Imaging is an important diagnostic tool, but it does not always tell the full story when it comes to SI joint dysfunction. Mechanical SI joint pain often produces no visible changes on standard imaging. A normal scan does not rule out the joint as a source of pain.
Myth: SI joint pain is just regular lower back pain.
While the two can overlap, SI joint dysfunction is a distinct condition with its own pattern of symptoms, causes, and anatomy. Treating it as generic back pain without identifying the actual source can lead to an extended period of discomfort that could otherwise be better understood and managed.
Myth: SI joint problems only affect older people.
SI joint dysfunction can affect people of a wide range of ages. Pregnancy-related SI joint pain often affects younger women, and inflammatory conditions involving the SI joint commonly begin in early adulthood.
Myth: Rest is always the best approach.
Complete rest is generally not recommended for most musculoskeletal pain, and SI joint dysfunction is no exception. Prolonged inactivity can actually worsen stiffness and may contribute to muscle weakness that reduces support around the joint. Gentle, appropriate movement is typically encouraged, though the right approach depends on the individual.
While everyone’s situation is different, there are general habits that support pelvic and spinal health and may help reduce strain on the SI joints over time.
Paying attention to your posture, especially when sitting for long periods, can make a meaningful difference. Try to sit with your weight distributed evenly across both hips and avoid crossing your legs habitually, since this can create uneven pressure across the pelvis.
When lifting, bending at the knees and engaging your core rather than bending straight forward from the waist helps protect the lower back and pelvis. This principle applies to everyday activities as much as it does to exercise.
Strengthening the muscles that support the pelvis, including the core, hip stabilizers, and glutes, is generally considered beneficial for SI joint stability. Low-impact movement options like walking, swimming, and gentle stretching are often well-tolerated.
Sleep position can also affect SI joint comfort. Sleeping on your side with a pillow between your knees may help keep the pelvis in a more neutral position and reduce discomfort overnight.
Maintaining a healthy body weight reduces the overall load placed on your joints, including the SI joints, which bear significant forces during walking and other daily activities.
If you have been experiencing lower back, buttock, or pelvic pain that is persistent, worsening, or interfering with your daily life, it is a good idea to speak with a healthcare provider. SI joint dysfunction is often underdiagnosed, and getting a proper evaluation can help clarify what is causing your symptoms.
There are also certain warning signs that should prompt you to seek care more promptly:
These symptoms can sometimes indicate a more serious underlying condition that warrants timely medical attention. A qualified provider can conduct a thorough evaluation, ask about your history, and use physical examination techniques to help determine whether the SI joint is the source of your discomfort.
Early attention to pelvic and lower back pain can help prevent a short-term problem from becoming a longer-term one. You do not have to simply live with pain that is affecting your quality of life.
Ready to learn more? Reach out to schedule a conversation with a provider who can help you understand your pain and your options.