What is piriformis syndrome?

Updated: Dec 21, 2018
  • Author: Shishir Shah, DO; Chief Editor: Sherwin SW Ho, MD  more...
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Answer

Low back pain (LBP), is ubiquitous. An estimated 30-45% of persons aged 18-55 years have some form of back pain in their lifetime. LBP most commonly involves one of the following conditions: sciatic nerve entrapment, herniated nucleus pulposus, direct trauma, muscle spasm due to chronic or overuse injury, or piriformis syndrome.

Piriformis syndrome (see the image below) is characterized by pain and instability. The location of the pain is often imprecise, but it is often present in the hip, coccyx, buttock, groin, or distal part of the leg. The history and physical findings are key elements in differentiating the more common forms of LBP and piriformis syndrome. The literature and general knowledge on piriformis syndrome is limited, compared with that of sciatica or disc herniation. However, the common findings associated with piriformis syndrome are agreed upon.

Nerve irritation in the herniated disk occurs at t Nerve irritation in the herniated disk occurs at the root (sciatic radiculitis). In piriformis syndrome, the irritation extends to the full thickness of the nerve (sciatic neuritis).

Yeoman first described piriformis syndrome in 1928 as periarthritis of the anterior sacroiliac joint. The history of this condition stems from one of many causes of lower back and leg pain. Many patients who underwent unsuccessful surgery in the lumbosacral region were later found to have piriformis syndrome.

For patient education resources, see the Osteoporosis and Bone Health Center and Back, Ribs, Neck, and Head Center, as well as Back Pain.


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