Piriformis Compressive Sciatica
posted by : Dr. Barnetton: 23 January, 2019
Piriformis compression of the Sciatic nerve is actually not the same as “Piriformis Syndrome”. This is probably why insurers doubt its existence, until one of them has it. Also known as “Fat Wallet Syndrome”, “pain in the butt syndrome”, (all searchable on Google), this differs in that there are no anatomical malformations as described by Yeoman in 1928. He did however correctly involve the Sacroiliac joint as one of the origins of Piriformis compressive Sciatica. In short the muscle is the largest of six hip ext. rotators. (moves your leg outward like exiting a car). It is unique in two ways: the only muscle to connect to the Sacroiliac joint and the only muscle spanning across the Sciatic nerve. Spasm, resulting in thickening, can irritate of compress some or all of the nerves within the Sciatic nerve. Often called Sciatica not of back origin. A misnomer, in that the actual Sciatic (think wiring harness) doesn’t form until the nerves merge anterior to the Sacroiliac joint and piriformis muscle. Just put a wallet in your pocket and go for a drive, you will rapidly experience piriformis compression, with limited or complete tingling, numbness, weakness or pain in the affected leg.
This classic picture shows the muscle attachment and position on the nerve.
The picture on the right shows what happens to the Sciatic nerve when one crosses their leg. That’s why we change that position often. I more often than not find it is of Sacroiliac Joint origin. If the joint is inflamed or moves,the muscle reacts, irritating the Sciatic. The muscle, like your calf muscles, cramps and hurts. How to fix it? Stretch it like one would a calf muscle, about ten times per day and it will improve. If the Sacroiliac is unstable, bracing or other treatments may be needed. Think of stretching a calf cramp with a sprained ankle, a similar dilemma.