Anatomy in Action Series: Paying Tribute to the Piriformis
By Laurie Mueller BA, DC, CFMP
What is the Piriformis?
The piriformis is a little muscle with a lot of power. It lies deep in the pelvis under the large gluteus maximus musculature along with other small, deep muscles, such as superior and inferior gemellus, quadratus femoris, and obturator internus and externus.
Its orientation is horizontal/diagonal, attaching to the lateral edge of the sacrum and the greater trochanter of the femur. As one of the six small rotator muscles, it serves to rotate the femur during hip extension and abduct the femur when flexing the hip. In lay terms for patients, it enables your hip to rotate and allows your leg and foot to turn outward.
Piriformis syndrome is a condition in which the piriformis muscle spasms and causes pain in the buttock. However, spasms of this little muscle have the potential to cause much greater pain.
Getting on Our Nerves
The power of the piriformis stems from its close proximity to the sciatic nerve. The sciatic nerve is the largest and longest nerve in the human body. It is actually a nerve bundle formed by the union of multiple nerve roots from the lower spine (mainly L4, L5, SI, S2, S3, for inquiring minds) that combine to travel through the pelvis, down the back of the thigh and all the way to the heel and sole of the foot to essentially provide nerve supply to a large portion of the leg.
Pressure on the nerve can be quite painful and create debilitating pain that radiates down the back of the leg, muscle weakness in the lower extremity or even sensations of pins and needles in the skin of the foot and lower lateral leg when it is compressed. In cases when symptoms affect the sciatic nerve, the pain is called 'sciatica/ The relationship between the piriformis and sciatic nerve can be a bit of a chicken-andegg conundrum, as spasm of the piriformis can contribute to nerve irritation, and sciatic impingement can lead to piriformis spasm.
Anatomically speaking, the sciatic nerve typically sits very near to the piriformis muscle as it makes its exit down to the leg. However, there is a very common anomaly in some people where the sciatic nerve will actually pierce the belly of the muscle, travelling through it rather than sitting next to it. Spasm of the muscle can create sciatic symptoms in either case. However, for patients whose nerve traverses through the belly of the muscle, the risk of nerve symptoms with piriformis spasm is much greater. It is estimated that 20% of the population exhibits the sciatic nerve piercing through the muscle.
Clinical Significance
During the process of differential diagnosis, your DC will need to ensure that the pain is coming from this small but mighty muscle and not something more significant. Inflammation from injury or other factors surrounding nerve compression will need to be evaluated in the process. Other potential issues that can cause sciatic pain include space-occupying lesions such as a herniated disc or disc bulge, or, less commonly, a tumor. Patients may be referred for an MRI if their examination and presentation warrants further evaluation.
Piriformis spasm can be influenced by a variety factors, ranging from irritation to the muscle from sitting too long, irritation to nearby structures like the sacrum or hip where it attaches, or injuries such as sprain or strain in the hip.
Doctors of chiropractic will address it by optimizing joint function in the region of the low back, hip and sacroiliac joint. They can also provide strategies to relax the muscle which may include muscle work in the office, applying physiotherapy modalities, or, in some cases, referring out for deep tissue massage.
Patient compliance and follow-through in performing recommended stretches that can be done at home are also extremely important for symptom resolution. There are several methods/positions in which it can be done, but the easiest is sitting in a chair with your back straight, knees and hips at 90-degree angles. Cross one ankle overthe opposite knee and gently apply pressure downward on the knee. Hold for 10 seconds. Release pressure, and with your hand on your knee, push up against your hand as a barrier. Perform several repetitions, and always do both sides. Have your DC demonstrate how to properly stretch the piriformis in varied positions so that you can also aid in instruction for patients.
Laurie Mueller, BA, DC, CFMP served in private practice in San Diego, California. She was the post-graduate director at Palmer College from 2000-2010; served as the ACC Post Graduate subcommittee chair for 6 years; peer reviewed for the Research Agenda Conference, and wrote the informal role determination study that aided in the development of FCLB's guidelines for chiropractic assistants (CCCAs). Dr. Mueller currently works as a private eLearning consultant with a focus on healthcare topics and functional medicine through her company, Impact Writing Solutions LLC, and subsidiaries www.CCCAonline.com and www. fxmedonline.com . She is a clinician, an educator and an expert in online educational pedagogy.
... "Haveyour DC demonstrate how to properly stretch the piriformis..."
