Piriformis syndrome-related articles

Selected articles and neurology and neurosurgery forum letters re: piriformis syndrome and sciatic pain
Piriformis Syndrome
Copyright © 1996-99 M.Steckel All Rights Reserved

This is a muscular problem which causes sciatic or leg pain. It is often mis-diagnosed because it can mimic other problems such as disc herniations which also present with leg pain. The good news is once properly diagnosed it’s usually quite easy to remedy.

The Anatomy

The piriformis muscle is a tiny muscle located deep in the buttock, underneath all the Glute muscles. It originates on the lateral aspect of the sacrum and inserts into the head of the femur. It aids in external rotation of the hip. Lie on your back with your feet pointing towards the ceiling. Rotate your foot outwards to point to the side. That’s what the piriformis muscle does. Seems pretty insignificant on it’s own, but problems arise because of the piriformis muscle’s relationship to the sciatic nerve.

The sciatic nerve is the largest nerve in the body. At it’s largest point it’s about the width of one’s thumb. It originates in the low back from numerous roots and then runs down the leg to supply all nervous system functions to the leg. On it’s way down the leg, it passes underneath the piriformis muscle. Some anatomic variations do exist: In some people the nerve passes over the piriformis muscle, in some it splits and passes around the piriformis and in others it passes through the piriformis. Problems arise when the piriformis muscle becomes tight because it will often compress the sciatic nerve which gives pain into the distribution of the nerve.

Signs and Symptoms

  • Deep aching in the buttock and thigh on the involved side. Usually not beyond the knee.
  • Pain is often aggravated by sitting, squatting or walking.
  • Affected leg is often externally rotated (toes point out) when relaxed, such as when lying face down on the bed with your feet over the end of the mattress.
  • Right leg often affected after driving a long distance if the foot has been in external rotation while depressing the gas pedal.
  • Often causes low back pain
  • Some reports suggest a 6:1 female to male predominance

What’s Going On

If the leg has been externally rotated for an extended period of time (such as when driving) the piriformis muscle can shorten. When you try to straighten out the involved leg the muscle compresses the sciatic nerve. If compressed long enough the nerve will cause aching in the leg and even pain in the low back.

The leg doesn’t necessarily have to have been externally rotated for a long time – piriformis syndrome may be a result of faulty foot or spinal mechanics, gait disturbances, poor posture or sitting habits or any other factor that could cause that muscle to function abnormally.

What To Do About It

Your first approach should be through stretching. Because this muscle isn’t usually stretched it may just be tight from running, etc. To stretch your RIGHT piriformis, start off by lying on your back. Bend your knees and cross your right leg over your left so your right ankle rests on your left knee in a figure four position. Now, bring your left leg towards your chest by bending at the hip. Reach through and grab your left thigh to help pull things towards your chest. Here’s a photo to help you picture this.

If you haven’t stretched your piriformis in the past, that may be all you need to do. If stretching alone doesn’t help then you’ll need to have someone check your pelvic and foot mechanics. As with ITB Syndrome, pelvic mechanics can play a role in piriformis syndrome. Because the piriformis muscle originates on the sacrum it can be directly influenced by poor pelvic mechanics. The good news is that it’s usually easily fixed. If your feet are contributing to the situation, you may need to get different running shoes or maybe orthotics. Also, you’ll want your doctor to review your work and non-work postures and positions to see if anything that you’re doing regularly may be contributing to the tightness of the muscle.

Here it is once again in a nutshell.

  • Stretch the Piriformis muscle (see Stretching for more detail)
  • Address faulty pelvic or foot mechanics
  • Address postural or work related contributing factors
  • Return to running gradually. Build up slowly to pre-injury training level.
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      Subject: Re: Other causes of sciatica?
      Forum: The Neurology and Neurosurgery Forum
      Topic Area: Spine
      Posted by CCF MD GS on January 14, 1999 at 13:36:04:
      In Reply to: Other causes of sciatica? posted by Jim on December 21, 1998 at 18:24:25:

      : I am 27 year old male who underwent a successful laminectomy in October of 1995 due to a sports injury. In October of this year, I jumped up and landed on my left heel. I immdeiately had a “shooting” pain all the way up to my kndney area. I really don’t have any back pain. My doctor thinks that there is probably no disc involvement this time, and I somehow irritated my sciatic nerve in the pelvis region or there abouts. My only symptom is difficulty in laying down, as I am able to sit, walk, stand, bend and lift without pain. When I lie down, my whole left leg swells up and I experience “pins and needles” in my outer chin and top of the foot. Thus I am unable to really sleep. I have a few questions. First, is it possible to have a sciatic problem without disc involvement (such as piriformis syndrome)? Second, could this be a scar tissue problem I hear so much about that suddenly manifested itself after my injury (my symptoms are the exact opposite of my previous symptoms in 1995)? Also, is scarring from laminectomies as prevelent as the posts on the internet suggest? Do you know of any long-term studies that show percentages of sufferers? I thank you in advance for your time and consideration.


      Thanks for your question and sorry to hear about your problems. It is unfortunate that you have had to undergo major back surgery at such a young age. I’m not sure how to explain why you are having swelling of your leg when you lie down? unless you are somehow obstructing your vascular or lymphatic flow but that does not make sense to me. There are several tests that can be done to help investigate your problem a little further. You could have an MRI of the lumbar spine to rule out a nerve impingement proble. An EMG study of the leg can be very helpful in diagnosing sciatic nerve injuries but I would still expect symptoms at other times as well. A CT scan of the pelvis could help rumle out an abnormality around your piriformis muscle. If all this is negative a vascular specialist could examine your leg for vascular problems. Scarring is not that major a problem but of course you hear alot about it because those are the people that will post questions. Hope this helps. If you wish a referral to CCF call 216 444 5559. Good luck

      This information is provided for general medical education purposes only. Please consult your doctor regarding diagnostic and treatment options.

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      Forum: The Neurology and Neurosurgery Forum
      Topic Area: Neurosurgery – General
      Posted by CCF NSG MD /gsh on August 11, 1998 at 22:29:56:
      In Reply to: SEVERE BACK PAIN AND SCIATICA posted by Natalie on August 11, 1998 at 09:20:12:

      : I had a laminectomy at L5-S1 on my right side on 6/1/98. After my surgery, my sciatica was gone and I was no longer in pain. I was walking three miles a day and was very active.
      : Four weeks ago, the sciatica came back with severe back pain, tightness in the butt, numbness in my leg, tingling, stabbing and pintching in my nerve. I cannot put pressure on my right leg without having severe pain. I went back for another MRI and they found the following:
      : There is desiccation of disc material at L4-5, 5-1 with mild posterior bulding at L4-5 unchaged fromt he prior exam. There is prominent soft tissue on the right side at the level of L5-S1 due to my laminectory. This tissue enchances diffusely with no evidence for recurrent disc.
      : My doctor is on vacation for the next two weeks. I would like to know what this report means. I am in constient pain and the pain medication is not working.
      : Please respond. I need to know what is going on and what is happening.


      Dear Natalie,
      Diffuse enhancement in a region that recently underwent surgery is the hallmark of scar formation. In your case it may be pinching on the nerve as it exits the foramen. The report does not note any significant disc herniation that would cause such pain.
      The best way to treat this for now is to go easy on the back for a while. Take something for pain and perhaps something to relax the muscles. Give it some time.
      Do let your physician know if the pain does not improve or gets any worse. He would likely want to evaluate you again as well as review the most recent MRI.
      Good luck.

      The Piriformis Syndrome
      Subject: Re: Numbness/Tingling in legs-Sciatica?
      Forum: The Neurology and Neurosurgery Forum
      Topic Area:
      Posted by ccf neuro M.D.* on March 15, 1998 at 00:03:30:
      In Reply to: Numbness/Tingling in legs-Sciatica? posted by LSW on March 07, 1998 at 23:06:07:

      : I was diagnosed with coccydynia (coccyx pain). In addition to the coccyx pain I have constant numbness and tingling in both legs and in my left arm. I also have intermittent pain in my legs from my buttocks down to my toes. I’ve received 3 epidural injections and am taking PT. I’m back to work after being off for 4 months. I’m doing a lot of sitting at work and the numbness and weakness has increased more than ever.
      : Originally I had an EMG test that was ok, but was told I had diminished sensations in the lower extremities with the pinprick test. I feel as if the numbness/tingling pain has been ignored with my treatment of coccydynia. I don’t know if the coccydynia has flaired up the sciatica or some other nearby nerves. I was told the injections would coat the nerves and help with inflammation. The coccyx pain has decreased with the inj. but after being off work 4 months and now sitting 80% of my working day I come home and lay down and put my feet up.
      : I’m wondering if I need another opinion. My brother’s neighbor an M.D. told him coccydynia should not ever give pain down the legs and that there is never any numbness produced, as the nerves that run down the legs have exited from the spine long before the coccyx.
      : I’m concerned the increased numbness, tightness, etc. in my legs may mean I’m doing additonal damage to something.
      : Any suggestions or comments?
      : Thank you. -LSW

      Hello LSW
      Let me first apologize for us missing your question and the associated delay. Sciatica is a very particular, specific variety of pain that begings in the lower back and shhots like lightning or an electric shock down to the back of the thighs and legs to the toes. Gradual pain, aching pain, and tingling are not indicative of sciatica. True sciatica is most often due to a herniated disk and can be detected by a bedside examination maneuver known as the straight leg raise. EMG is an electrical test used to study whether there is any damage to any nerve roots in the lower back. Coccidynia is pain in the coccyx and does not produce sciatica, or any leg symptoms. The presence of such symptoms in the legs would suggest an additional problem may be going on. Sometimes one can have inflammation of the nerve roots in the back without actual damage that would be detected by EMG. Antiinflammatory drugs or epidural cortisone injections are good ways to try and treat such inflammation. Another condition to beware of that is sometimes very difficult to diagnose is one known as lumbar canal stenosis. This very gradual onset problem produces tingling, pain, and even weakness sometimes in several nerve roots in the legs, triggered by prolonged standing, walking, or sometimes even sitting. The telltale sign of this condition is that pain or numbness someone chronically has from it disappears or is greatly relieved when they are pushing a shopping cart, or are in a similarly stooped position. Only a CT scan or MRI scan of the lumbar spine (lower back) can diagnose thia problem, and ONLY surgery can fix it— epidurals and drugs will NEVER help it or fix it. If you would be interested in a second opinion at the Cleveland Clinic, our department of neurology’s phone number is 1-800-223-2273, extension 45559. Another alternative would be our spine center. Please remember that information provided on the forum is intended for general medical informational purposes only, and that the actual diagnosis and treatment of your specific medical condition should be strictly in conjunction with your current treating physicians. We hope you find the information useful.

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      Subject: Re: Leg weakness/numbness
      Forum: The Neurology and Neurosurgery Forum
      Topic Area: Neuropathy
      Posted by CCF neuro MD MM on December 05, 1998 at 16:00:38:
      In Reply to: Leg weakness/numbness posted by Tim on December 05, 1998 at 15:49:26:

      : I am a 35yo male. I have suffered from a weakness in the left leg/ankle for approximately 6/7 months. Numbness in the lower left extremity is also prevalent. My left leg sometimes feels jumpy, especially at night….
      : I consulted my PCP, who referred me to neurologist. My blood work was normal, no blood in the stool, etc…. blood pressure normal. No bowel or urinary problems. I have started walking with a slight limp on some days. The problem seems affected by the type of shoes I wear or the amount of walking I do. A walk in the mall causes problems.
      : The neurologist performed an EMG on the LLE… results were fine.
      : My PCP referred me to my orthopedic surgeon. His conclusion, my reflexes were extremely strong in the lower part of my body. My clonus in the right leg was about 6 beats, my left leg about 2 to 3. Everything else seemed fine. I was diagnosed with sciatica about 7 years ago by this same orthopedic surgeon. He feels my reflexes are hypersensitive in the lower part of my body…therefore he is sending me back to the neurosurgeon.
      : Just curious… what could the problem be?


      There is insufficient information available (to anyone ) at this stage to make a definite diagnosis but a few things are obvious.
      Clonus is known as an upper motor neuron sign, this means that it is generated by compromise of the nerve supply to a muscle somewhere in the brain or spinal cord, not in the peripheral nerve.
      For this reason sciatica is not the cause of the problem because clonus is not a feature of sciatica. I do think you need to be seen again by a neurosurgeon or neurologist and have this reassessed, you will probably need an MRI scan of your brain or spinal cord or both, to clarify what is cauusing the problem.
      It is possible to say WHERE the problem lies to some extent but not to sat WHAT the underlying cause is, it could be a simple as a disc high up in the spine which is pressing directly on the spinal cord itself rather than on a nerve root, which is what causes sciatica.

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      Subject: Re: Piriformis syndrome
      Forum: The Neurology and Neurosurgery Forum
      Topic Area: Neuromuscular
      Posted by CCF Neurology MD:NT on December 21, 1998 at 19:48:51:
      In Reply to: Piriformis syndrome posted by devan on December 20, 1998 at 23:27:52:

      : Is there an easy way to diagnose piriformis syndrome? Will my primary care physician be able to diagnose it or do I need to see a specialist? How can it be treated? Is there a permanent cure? Are there physicians in the Philadelphia area who can be consulted? Thanks.


      Dear Devan:
      Piriformis syndrome is a controversial entity. Non-neurologists often diagnose this syndrome when there is a patient who has leg pain that is worsened by pressure in the buttock area, and relieved by blocks in that area. When critically reviewed, there are very few, if any cases of a convincing piriformis syndrome in which there is clear evidence of sciatic neuropathy because of compression by the piriform muscle. Most cases that are felt to have the syndrome have either non-neurological causes of leg pain, or else have a lumbosacral radiculopathy or sciatic neuropathy/sacral plexopathy from other cause.
      Most neuromuscular experts do not really believe in the existence of the piriformis syndrome.
      I would suggest a consultation with one of the neuromuscular experts at Univ Penn, Temple, or Johns Hopkins to correctly diagnose the problem.

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      Subject: Re: Sciatica
      Forum: The Neurology and Neurosurgery Forum
      Topic Area: Neuromuscular
      Posted by CCF Neurology MD – AY on January 07, 1999 at 17:46:28:
      In Reply to: Sciatica posted by Wayne on January 07, 1999 at 09:43:11:

      : Among my other assorted neuromuscular problems (twitching off and on, recovery from c-spine surgery, etc.), it now seems that I have sciatica or something very much like it. It began weeks ago with a relatively brief period in which I had intense pain radiating from my buttocks down the back of my leg into my foot. That subsided quickly only to be replaced by something far more irritating… a constant “tickling” in the same general areas. The “tickling” or crawling sensation is driving me quite mad. I’ve tried anti-inflammatory (off and on; not consistently I admit), hot baths and anything else I can think of. The only temporary relief I can get (oddly) is if I stretch my hamstring by sitting on the floor and leaning forward onto my leg. My leg also feels “tight,” not stiff exactly but almost as though it’s hesitating when I step forward. If I take a forceful step forward (and stretch the hamstring), it stops the tickling and actually brings some sort of relief. Question — what is this and how do I stop the tickling? When will it likely go away (I’ve now had it for about seven weeks!). Thanks.


      Thanks for your question. Although not very common, the symptoms described
      in your message could be a manifestation of a mild radiculopathy, that is,
      a compression/entrapment of the nerve roots as they leave the spine. The
      presence of fairly typical radicular-type pain preceding your current symptoms
      further reinforces this hypothesis. Despite the relatively benign (although
      quite annoying) nature of your current symptoms, it would be advisable to
      further evaluate your lumbar spine to rule-out the possibility of a more
      ominous/serious structural problem. One investigational step would be to
      obtain a neuro-imaging study (preferably a MRI scan of the lumbar spine).
      If alterations are seen in the MRI scan, one should consider the necessity
      of an electrodiagnostic test, such as an electromyogram (EMG). Please
      discuss these possibilities with your physician.
      I hope this information is helpful. Best of luck.
      This information is provided for general medical education purposes only.
      Please consult your doctor regarding diagnostic and treatment options.

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      The Pirifornis Syndrome
      researched by Roger Fontaine
      In House Massage Clinic

      Introduction. Not all low back, hip, and gluteal (buttock) pain are manifestations of back injury. Pain in any of these areas may indicate injury or irritation of any one of a number of muscles and nerves surrounding the low back and hip. Injury to any of these structures can result in pain and loss of function. A specific muscle that is susceptible to injury and inflammation is the piriformis muscle. Due to the location of this muscle, the sciatic nerve is often involved with piriformis problems. Pain and dysfunction resulting from piriformis injury is referred to as piriformis syndrome. The symptoms of this disorder sometimes mimic those of a bulging lumbar disc, or similar low back injury. Therefore, diagnosis of pain in the low back, gluteal, or hip region should include an evaluation of the piriformis muscle (PM), other hip musculature, and surrounding nerves.

      Anatomy and Function. The piriformis muscle is located deep in the gluteal region. This muscle attaches to the sacrum and the lateral portion of the upper part of the femur. It is one part of a group of muscles whose actions include abduction (moving the thigh away from the midline) and external rotation of the thigh (turning the knee and toes outward). These muscles are important in maintaining stability of the hip in all weight bearing activities.
      The sciatic nerve passes between the piriformis muscle and a notch in the pelvis as it enters the gluteal region. This large nerve supplies a majority of the nervous innervation to the lower extremity. In some cases, the PM may be split into two bellies, with the sciatic nerve passing in between the two portions. The sciatic nerve also may be split into two trunks which may pass through different portions of the PM (1). In any of these arrangements, the sciatic nerve is susceptible to compression between the piriformis and the pelvis.

      The PM is susceptible to hypertrophy, an increase in size, as a result of its high level of activation. With increased use, muscles increase size and strength. During the weight bearing portion of gait, the piriformis is lengthened which initiates a stretch reflex and results in contraction. During the swing phase of gait, the piriformis contracts again to assist with external rotation (1). This double activation may precipitate muscular hypertrophy, thereby decreasing the space available for the sciatic nerve.

      Symptoms and Diagnosis. Symptoms of piriformis syndrome often include deep buttock and posterior hip pain. The gluteal discomfort may be accompanied by pain, numbness, and tingling, that radiates into the posterior thigh, leg, and foot. These symptoms are generally associated with a condition known as sciatica. Sciatica pain is often the result of nerve compression in the spinal cord associated with a herniated lumbar disc (2,3). Generally this type of low back injury also will be accompanied by neurological deficits that are absent with piriformis syndrome.

      The pain and discomfort of piriformis syndrome are usually exacerbated by standing after prolonged sitting and with activity. Pain is minimized when lying down with the hips slightly flexed, in a curled up position. Tightness and sensitivity may be revealed during palpation of the PM. The PM is stretched when the body is rotated around a planted foot, as in a tennis serve. This motion will reproduce pain. Resisted abduction in the seated position should reproduce discomfort in the PM.

      Diagnosis of piriformis syndrome may be delayed or missed completely without a thorough examination. Often, piriformis syndrome is diagnosed after other causes of sciatica have been ruled out (2,3).

      Suggested etiology of piriformis syndrome begins with injury to the PM or the pelvis. Trauma to the PM may result in spasm, edema, contracture, and finally compression and entrapment of the sciatic nerve (1). Hypertrophy or extreme tightness of the piriformis also may compress the sciatic nerve. Piriformis tightness can result from increased lumbar lordosis, swayed low back, and concurrent hip flexor tightness (4). Improper biomechanics, muscle imbalance, and leg length discrepancies may contribute to piriformis problems.

      Treatment. Although there appear to be numerous causes of piriformis syndrome, the treatment approach follows a consistent pattern. Treatment of piriformis syndrome should focus on reducing the compression of the sciatic nerve. If compression is the result of inflammation of the PM and or the sciatic nerve, ice can be effective in reducing edema and pain. Ice should be applied directly over the piriformis muscle, which lies just beneath the hip dimple, for 20 to 30 minutes several times per day. Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen and naproxen can help control inflammation and pain (4). Rest also may be indicated in order to prevent re-injury.

      Passive stretching of tight musculature, too, is important in restoring normal range of motion and function. The correction of biomechanical errors and leg length discrepancies are important (1,4,5). Through gait analysis and physical examination, an athletic trainer, physical therapist, podiatrist, or physician can diagnose gait errors, muscle imbalance, and limb length discrepancies. Muscle strengthening and body mechanics education can correct the biomechanical errors while the prescription of foot orthoses can compensate for leg length differences. Achievement of a normal range of motion should be the first goal. Once adequate range of motion is acquired, strengthening exercises may then be added to correct any muscle imbalances. If these conservative treatments of ice, NSAIDs, stretching, and biomechanical corrections, are ineffective, corticosteroid injections may be prescribed. In extremely resistant cases, surgical release of the piriformis muscle may be indicated.

      Stretching protocols involve hip flexion, adduction, and internal rotation applied with slow steady pressure. Once inflammation has been resolved, heat modalities such as ultrasound, whirlpool, and moist heat can be used prior to stretching to improve the elasticity of the tissues being stretched. The application of ultrasound should be supervised by a physical therapist or athletic trainer. Moist heat can be applied over the PM and proximal musculature for 15 minutes. A cloth should be placed between the skin and the heat pack to protect against burning. Maintaining normal range of motion will help alleviate symptoms, as well as prevent progression and recurrence of symptoms.

      Correction of biomechanical and training errors are also important in the treatment and prevention as are leg length discrepancies and muscle imbalances. As stated earlier, there are a number of health professionals who can assess the structure and function of the hip and lower extremity. Abnormalities in any of the components of gait: limb length, joint range of motion, muscle function, strength balance, and coordination of movement, can result in added stress on the piriformis muscle. A controlled program of stretching, strengthening, and mechanic education with the correction of structural problems can help to alleviate symptoms and prevent recurrence. Alternative methods of training may also be helpful. Aquatic therapy, changes in the regular running surface, and a change in training volume are options that could be considered.

      In determining the diagnosis for low back, gluteal, hip, and lower extremity pain the examination should include an assessment of piriformis health and function. Pain resulting from compression of the sciatic nerve by the PM sciatic nerve can be managed and prevented from recurring. Inflammation can be reduced with ice, NSAIDs, and rest. Further treatment of hypertrophy and tightness includes stretching protocols and correction of biomechanical and structural abnormalities. Education regarding the progression of the disorder also may help the individual manage and limit the recurrence of piriformis syndrome.

      (1) Julsrud, M. E. (1989). Piriformis syndrome. Journal of the American Podiatric Medical Association, 79, 128-131.
      (2) Chen, W. S. (1992). Sciatica due to piriformis pyomyositis. The Journal of Bone and Joint Surgery, 74-A, 1546-1548.
      (3) Vandertop, W. P., and Bosma, N. J. (1991). The piriformis syndrome. The Journal of Bone and Joint Surgery, 73-A, 1095-1097.
      (4) Keskula, D. R. and Tamburello, M. (1992). Conservative management of piriformis syndrome. Journal of Athletic Training, 27, 102-108.
      (5) Barton, P. (1991). Piriformis syndrome: a rational approach to management. Pain, 47, 345-352.