A Common Cause of Low Back and Sciatic Pain – The Piriformis
As a licensed massage therapist, I specialize in chronic pain and injury management using deep tissue massage therapy. Most of my clients come in with a common complaint: pain in the low back, hips (primarily on one side), and/or shooting pain or numbness down the back of the leg.
More than two million Americans suffer either from back pain or a form of sciatica that is often misdiagnosed and improperly treated. Many suffer from pain for months or years without a proper diagnosis. I work with these symptoms so frequently that I have noticed some common characteristics with this all-too-common pain complaint.
The most common characteristic I find are aggravated trigger points (TrPs) in the piriformis muscle. Piriformis trigger points are often confused for a herniated disc, sciatica, or other back issues, and many sufferers undergo unnecessary and costly tests, injections, and surgeries.
What is the piriformis?
The piriformis muscle is a small external rotator of the hip whose function primarily is to turn the knee and foot outward. It lies deep within the gluteal muscles, originates from the sacral spine, and attaches to the greater trochanter of the femur – the big bony “bump” on the outside top of the thigh. The sciatic nerve passes beneath through an opening called the sciatic notch.
In non-weight bearing activities, foot unloaded and hip extended, the piriformis rotates the thigh outward. When the hip is flexed at 90 degrees it aids in hip abduction.
In weight bearing activities, foot loaded, the pirifomis is often needed to control rapid medial rotation of the thigh – for example, as the foot strikes the ground during walking or running, the knee turns inward.
Piriformis Trigger Points (TrPs)
The myofascial pain component includes pain in the low back, groin, buttock, and hip. A TrP may cause the muscle to compress and irritate the sciatic nerve, causing the pain to travel along the course of the nerve. The pain may radiate down the back of the leg and into the hamstrings, the calf muscles, and possibly the foot. The pain may initially be confused with a hamstring strain. Weakness, stiffness and a general restriction of movement are also quite common. Tingling, numbness, or shooting pains down the leg can also be experienced. Symptoms tend to be aggravated by prolonged sitting or by intense activity.
Piriformis TrPs are predominantly caused by a shortening or tightening of the piriformis muscle. Piriformis TrPs are commonly associated with sports that require a lot of running, change of direction, or weight-bearing activity. Piriformis TrPs can result from acute overload (as when catching oneself from a fall), from repetitive overload (as with the rapid internal rotation of the weight bearing experienced by walkers and runners with poor biomechanics), or from sustained overload (as when holding the leg bent and turned outward for prolonged periods while driving a car or working at a desk). Sciatic pain from piriformis TrPs is also a common complaint during pregnancy.
The piriformis muscle is responsible for the symptoms of pain by projecting pain from activation of the TrPs and by nerve entrapment upon the sciatic nerve. Once TrPs are activated, the piriformis muscle begins to put pressure on the sciatic nerve. The sciatic nerve runs under (and sometimes through) the piriformis muscle on its way out of the pelvis. The piriformis muscle can squeeze and irritate the sciatic nerve in this area, leading to the symptoms of sciatica.