Did you know that the SI joint can refer pain down the leg very similarly to sciatica? At The Movement Boutique, many of our patients come in already “diagnosed” with sciatica by a friend or family member (or Dr. Google!) and are surprised to learn that they are actually experiencing SI joint dysfunction. With so many causes of back pain, and sciatica leading the way on the internet, it can be difficult to decode on your own. Especially when the search term includes back pain that ‘goes down the leg’. Because of things like the start of ski season, snow shovelling, high heels at Christmas parties and carting around those holiday shopping bags, these types of injuries are especially common during the winter months
So, what’s the difference and what do they have in common?
Our SI joints are located under your thumbs when you put your hands on your hips. They serve both a stabilizing and shock absorbing function. The SI joint’s main purpose is to connect our sacrum (which is the bone at the base of our spine) to our iliac crest (aka our pelvic bone) and support our upper body weight. Since it serves a weight bearing function, the joint is generally quite stable with minimal, but necessary range of motion. SI joint dysfunction can be caused by a variety of things such as pregnancy, weight gain, or repeated movements that put stress on the joint and muscles. Sciatica, on the other hand, is often more serious and caused by irritation of the sciatic nerve (a long nerve that runs from lower lumbar spine all the way down the back of the leg. It’s common for people with bulging or herniated discs (more common under age 45) or an encroachment due to degeneration (more common over 45) to experience sciatica.
Many times, sciatica symptoms and SI joint dysfunction can mimic each other, so one can easily be mistaken for the other. Both types of injuries can be experienced as an intense sensation (sometimes described as an “electrical shock”) starting in the lower back and travelling down the back of the leg. That’s why in many cases, when you go to your GP and describe the pain, they will assume it’s the sciatic nerve, but the truth is, not all pain that travels down the back of the leg is necessarily sciatica.
To get it properly assessed and diagnosed, we recommend seeing a qualified practitioner and if you’re local, this is something we see on the regular at TMB. In the meantime, we wanted to give you some tips to help you differentiate the two. Please note that everyone is different and these factors can sometimes overlap when it comes to sciatica and SI joint dysfunction, but it should serve as a helpful starting point to paint a clearer picture for you!
While neither will technically show up on an x-ray, the signs of sciatica will show up on an MRI.
If the MRI imaging is negative, then it might be a clue that you have SI joint dysfunction.
**Keep in mind that imaging does not always correlate with functional problems. One of Dr. Bhat’s favourite analogies to illustrate this is to picture a photograph of a car parked in an auto body shop. Can you tell if the car has just been dropped off or ready for pick-up just by looking at the photo? NO! Similarly, you can’t tell just by looking at an image if there’s a functional injury. It needs to be properly assessed by a professional.**
2. Referred Pain vs. Radiating Pain
Radiating pain is pain with which a nerve is the actual source, forming a direct line from the sciatic nerve (in this case, the source) to other areas of the body. This is more so the type of pain you’d experience with sciatica.
Referred pain can be felt in other parts of the body other than the actual source. The source can be the SI joint, but you feel it in the low back and/or down the outside of the leg to the knee.
3. Trigger Points
Sciatica – Trigger point release (pressing down on the area) worsens the pain. If you press down on the part that hurts and you continue to feel an “electric shock” type of feeling, then it’s more likely sciatica from nerve irritation.
SI joint – Trigger point release will help the pain subside. The soleus muscle can play a big part in SI joint problems. In fact, a trigger point in the soleus muscle and the posterior fascia sleeve goes all the way up the back of the legs and into the SI joint. Other trigger points here include the glutes, hips and right below the lower ribs. If you press down on any of these trigger points and you notice pain relief or more mobility, then it’s more likely you have SI joint dysfunction.
4. Aggravating & Relieving Positions
Sciatica – Bending over, twisting, carrying heavy loads etc. would aggravate the injury. Lying on your tummy on your elbows with your chest lifted (this is known as the “McKenzie stretch”) or lying on your back with your knees bent on a chair would relieve the pain.
SI joint – Driving or sitting with your pelvis slouched (or body slightly rotated) with your legs above the rest of your body (think lying on a hammock) for prolonged periods of time would aggravate the injury. Pregnancy can also cause it.
5. Pain Location
Sciatica – Very sharp “electric shock” like pain that can easily be traced deep in the glutes, down the back of the leg, most frequently into the foot.
SI joint – Diffuse pain that is typically felt in the lower back, hip, leg, and/or groin and the patient might have a tough time narrowing down exactly where they feel the pain.
At TMB, if a patient points the pain using their hand, it’s likely diffuse pain (SI joint), whereas if they use their finger to trace the exact path of their pain, it’s more likely nerve irritation (sciatica).
6. Character of Pain
Sciatica – An “electric shock feeling” that you can trace with your finger and your sensory might also be off (numb, tingly “pins & needles” feeling on the bottom or side of foot).
SI joint – More of a diffuse, sharp or achy pain that can, depending on severity, travel down the leg (usually no further than the knee) and feels heavy and/or sore.
Barring a traumatic fracture-causing case of either, requiring surgery, conservative care is recommended for both. This would include acupuncture, spinal mobilization, fascial release, low-inflammatory diet, rest from aggravating activities and icing. At TMB, we also suggest natural anti-inflammatory supplements like Curcumin and Inflammatone
About The Movement Boutique in Toronto – Pilates, Chiropractic, Functional Medicine
Located on Yonge Street in Toronto, The Movement Boutique serves the areas of Summerhill, Rosedale and Yorkdale with Pilates classes and much more. Our philosophy is centred on a holistic, multimodal approach to health, grounded in the latest therapeutic techniques and clinical research. Our approach: Optimal health cannot be attained through a single therapeutic lens; injuries are often the result of a constellation of lifestyle issues, including dysfunctional movement patterns, trauma, nutritional deficiencies or destructive habits of mind.