National Associaltion of Myofascial Trigger Point Therapists - Symptom Checker

This is the technical name of the muscle being described.  This name may be used to find additional information in any medical resource. Piriformis
A group of muscles generally denotes muscles of the same function and may share a common attachment point. Hip Flexor
Muscle function, in this definition, is what the muscle could do if it was to contract by itself with the body in anatomical position.  This is a general definition of muscle function.  For more information on how muscles work together on the body please refer to a physiology or functional anatomy text.

Lateral rotation of the thigh.

A description of where a Myofascial Trigger Point may produce pain in the body.  This area is generally located away from the trigger point.

Pain is referred to the sacroiliac joint (SI) region, the buttock, and over the posterior hip joint.  Sometimes the pain extends over the proximal 2/3 of the posterior thigh.

A description of the symptoms a person may experience with trigger points in the muscle being described.

A person with TrPs in the piriformis muscle may have pain from the    TrPs as well as pain from entrapment of nerves that pass within close proximity to the muscle.  TrPs will cause a person to experience low back pain, buttock pain, hip pain, and posterior thigh pain.  Rectal pain during defecation is also noted.

Entrapment of the gluteal nerves could cause buttock pain.  Pressure on the sciatic nerve can cause pain and paresthesias in the posterior thigh and even project as far down as the leg and foot.  In these cases of “sciatica” a person should have the piriformis examined for TrPs so that a needless laminectomy is not performed.

SI joint displacement is also likely to exist with this myofascial syndrome.


 A list of possible diseases that fit the information derived from examination of a patient.

  1. Episacroiliac lipoma.
  2. Herniated intervertebral disc.
  3. Facet syndrome.
  4. Spinal stenosis.
  5. Sacroiliitis

A list of activities or positions that may either CAUSE a trigger point to manifest or PROLONG a pain condition respectively.

  1. Catching oneself in a fall can overload the piriformis.
  2. A wallet being carried in the back pocket can activate and perpetuate TrPs as well as increase compression on entrapped nerves.
  3. Direct trauma to the muscle.
  4. Driving a car for long periods with the foot on the accelerator.  In this position the foot is usually rotated outward, which is contracting the piriformis.
  5. Chronic pelvic inflammatory disease (PID) may perpetuate TrPs.
  6. Infectious sacroiliitis.
  7. Arthritis of the hip joint.
  8. Morton foot structure.
  9. Lower limb length inequality.

A corrective action is usually a modification of daily routine which will reduce stress on the affected muscle(s) in a person with myofascial trigger points.

  1. A shoe lift may be needed to correct a lower limb length inequality.
  2. When sleeping on the side, a person should place a pillow between the knees with the support extending to the ankles.
  3. Use of cruse control on long automobile trips will take tension off the piriformis as well as allow some movement for the lower extremity.
  4. Place the wallet in the front pocket to avoid compression of the piriformis as well as other muscles in the area.
  5. Correct Morton foot structure using the proper orthotics.
  6. When sitting at home or at work a person should change position often.  A rocking chair will limit immobility of the pirifomis as well as other muscles.

References : 
Simons DG, Travell JG, Simons LS, Myofascial Pain and Dysfunction: The Trigger Point Manual, vol 1, 2nd Ed. Baltimore: Williams and Wilkins, 1999.

Travell JG, Simons DG, Myofascial Pain and Dysfunction, vol 2. Baltimore: Williams & Wilkins, 1992.

This information is not intended to diagnose, treat, or cure any disease.  A proper diagnosis should be sought from a licensed health care provider.