Piriformis Syndrome Overview

The piriformis is a muscle that is behind the hip joint in the buttocks. The piriformis muscle is small compared to other muscles around the hip and thigh, and it aids in external rotation (turning out) of the hip joint. The piriformis muscle and its tendon have a close relationship to the sciatic nerve—the largest nerve in the body—which supplies the lower extremities with motor and sensory function. The piriformis tendon and sciatic nerve cross each other behind the hip joint, in the deep buttock. Both structures are about one centimeter in diameter. The condition of piriformis syndrome has been described as an irritation of the sciatic nerve from the piriformis muscle. There is controversy about whether this represents a distinctive diagnostic entity, although it has been described numerous times in the medical literature.

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Cause

When people are diagnosed with piriformis syndrome, it is thought that the piriformis tendon may be tethering the sciatic nerve, causing irritation to the nerve. While it has not been proven, the theory supported by many physicians is that when the piriformis muscle and its tendon are too tight, the sciatic nerve is pinched. This may decrease blood flow to the nerve and irritate the nerve as a result of pressure. Most doctors believe that piriformis syndrome occurs as a result of anatomic variation of the muscle and tendon. It is thought that, in some people, this relationship causes irritation to the nerve, leading to symptoms of sciatica.

Symptoms

Common signs and symptoms experienced by people who have been diagnosed with piriformis syndrome include:

  • Pain behind the hip in the buttocks
  • Electric shock pains traveling down the back of the lower extremity
  • Numbness in the lower extremity
  • Tenderness with pressure on the piriformis muscle (often causing pain with sitting on hard chairs)

Some people develop symptoms abruptly, while others note the gradual increase in symptoms of the back of their thigh. Most people who are diagnosed with piriformis syndrome are generally active people who experience increasing difficulty with certain types of athletic activity as a result of the symptoms of discomfort in the back of their thigh.

Diagnosis

There are no specific tests that can accurately diagnose piriformis syndrome. Many doctors will order tests, including MRIs and nerve conduction studies, but these are often normal. Because piriformis syndrome is difficult to diagnose, there are likely many cases of misdiagnosis. This means that some people with the condition don't have a piriformis diagnosis. In addition, some people with vague hip pain may receive this diagnosis even if they don't have the condition.

Sometimes referred to as "deep buttock pain," other causes of this type of pain include spine problems like herniated discs, spinal stenosis, and radiculopathy (sciatica), along with other problems like hip bursitis. The diagnosis of piriformis syndrome is often given when all of these diagnoses are eliminated as possible causes of pain.

When there is uncertainty in the diagnosis, often an injection is administered in the area of the piriformis muscle. There are different medications that can be injected, but often performing an injection can help determine the specific location of the discomfort. Typically, when an injection is given into the piriformis muscle or tendon, this is administered by ultrasound guidance to ensure the needle is delivering medication to the correct location.

Treatment

Unfortunately, the treatment of piriformis syndrome is quite general, and often this is a difficult condition to recover from. Common treatment suggestions include the following.

  • Rest: Avoid activities that cause symptoms for at least a few weeks.
  • Physical therapy: Emphasize stretching and strengthening the hip rotator muscles.
  • Anti-inflammatory medication: To decrease inflammation around the tendon.
  • Deep massage: Advocated by some physicians.
  • Cortisone injections: Injections in the area of the piriformis tendon may decrease inflammation and swelling.
  • Botulinum toxin injection: Injections of botulinum toxin can paralyze the muscle, reducing pain and discomfort.

In rare circumstances, surgery can be performed to loosen the piriformis tendon, called a piriformis release. This surgical procedure should only be considered when simple treatments have been tried for a minimum of 6 months, and when other common causes of pain have been evaluated and ruled out. While the surgery is straightforward, it is invasive, and recovery takes several months.

A Word From Verywell

Piriformis syndrome is a controversial diagnosis. Some doctors treat this condition regularly, while others do not believe it exists as a specific diagnostic entity. There are no agreed-upon criteria to establish the diagnosis of piriformis syndrome, and testing for the procedure is generally performed to eliminate other possible diagnoses rather than to confirm that piriformis syndrome exists. Most treatment protocols are aimed at improving range of motion and flexibility around the hip as well as diminishing inflammation around the sciatic nerve.

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3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Cass SP. Piriformis syndrome: a cause of nondiscogenic sciatica. Curr Sports Med Rep. 2015;14(1):41-4. doi:10.1249/JSR.0000000000000110

  2. Jankovic D, Peng P, Van Zundert A. Brief review: piriformis syndrome: etiology, diagnosis, and management. Can J Anaesth. 2013;60(10):1003-12. doi:10.1007/s12630-013-0009-5

  3. Bardowski EA, Byrd JWT. Piriformis injection: an ultrasound-guided techniqueArthrosc Tech. 2019;8(12):e1457–e1461. Published 2019 Nov 13. doi:10.1016/j.eats.2019.07.033

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