Piriformis muscle / Sciatic nerve



priformis muscle sciatic nerve


If you or your loved one has back pain, this article can be very useful for you.         


Piriformis syndrome

Piriformis muscle

Sciatic nerve

The location of the sciatic nerve

What causes piriformis syndrome?

What are the symptoms and features of piriformis syndrome?

What are the features and symptoms of sciatica?

The difference between sciatica and piriformis syndrome

Diagnosis of piriformis syndrome

Treatment of piriformis syndrome


Piriformis Syndrome:

The piriformis muscle and the sciatic nerve are located next to each other deep in the pelvis. This proximity is such that contraction and spasm of the piriformis muscle can damage part of the adjacent sciatic nerve or put pressure on it. Damage to the sciatic nerve causes inflammation and pain that spreads to the buttocks and back of the thighs. We call this clinical condition "piriformis syndrome". This type of back pain is different from the back pain caused by damage to the spinal cord roots of the sciatic nerve, commonly known as "sciatica".


Periformis muscle:

Deep inside the pelvis and on each side (right and left) of the spine, there is a small, smooth muscle where one side of it is attached to the bone at the end of the spine (sacrum) while the other side is connected to the top of the femur (the bone inside our thigh). This muscle contracts when our thigh moves away from the center of the body or rotates outward. The piriformis muscle is like a band that stretches from the sacral bone to the top of the femur. The importance of this muscle is determined when we know that the trunk of the sciatic nerve in the pelvis passes just below this muscle, and as mentioned above, spasm and contraction of the piriformis muscle can put pressure on the sciatic nerve and make it irritated and/or inflamed.


piriformis muscle


Sciatic nerve:

The trunk of the sciatic nerve is the thickest nerve in the human body, which is formed through the joining of five roots of the spinal nerve. This nerve trunk passes under the piriformis muscle. It is interesting to note that the position of the piriformis muscle relative to the sciatic nerve can be in four different pattern in human being. It is because of this anatomic differences in priformis muscle and sciatic nerve relation that people experiance different kind of signs and symptoms of piriformis syndrome. 


The location of the sciatic nerve:

In most people, the sciatic nerve passes under the piriformis muscle. In some, a branch of the sciatic nerve separates above the piriformis muscle, passes over the muscle, and sometimes passes through the piriformis muscle. In some other people, the entire trunk of the sciatic nerve passes through the muscle.

piriformis  muscle

What causes piriformis syndrome?

Inappropriate exercise and body movements upset the balance between the forces acting on the pelvis. In other words, disturbing the balance of forces which act as natural biomechanics of the pelvis, causes the piriformis muscle to stiffen and shorten due to unbalanced forces. The sciatic nerve is adjacent to it and this is how this pressure causes inflammation of that part of the sciatic nerve and causes symptoms. With long cycling, skiing, and similar exercises, piriformis syndrome should be expected.  


What are the symptoms and features of piriformis syndrome?

  • It is a prolonged and chronic pain that is felt in the buttocks and back of the pelvis.
  • The pain can also spread to the back of the thigh or lower back.
  • The pain in the morning is more when getting out of bed.
  • There may be pain in the penis.
  • The patient may complain of pain when urinating or defecating.
  • The pain increases with some movements of the thigh (especially turning the thigh inward and bringing the thigh closer to the midline of the body)
  • In patients with this syndrome, pain in the buttocks and pelvis is felt when the patient lies on his back and lifts the entire lower limb directly from the hip joint without bending the knee (this test is called Straight Leg Raising test or SLR).
  • In piriformis syndrome, applying pressure to the back of the pelvis and buttocks causes pain.


What are the features and symptoms of sciatica?

Pain caused by the pressing and inflammation of the sciatic nerve by intervertebral disc herniation and degenerative changes of the vertebrae (presence of bony spines) is usually a pain that starts in the lower back and extends through the buttocks, back of the thigh, back of the leg and sole of the foot. Sometimes pain and tightness are felt on the outer edge of the leg. This pain is sometimes accompanied by cramps in the leg muscles. Tingling and leg numbness, can occur with or without pain and cramping. Prolonged damage and inflammation of the sciatic nerve can be accompanied by weight loss, weakness and sometimes numbness of some muscles. The patient's pain may be aggravated by sneezing, sitting and coughing.


The difference between sciatica and piriformis syndrome:

To distinguish between sciatica and piriformis syndromes, you should note that low back pain is more common in sciatica, meaning that the pain of piriformis syndrome can be limited to the buttocks, back and upper thighs. Also there is no leg involvement or pain in piriformis syndrome. Finally, sciatica pain is not usually associated and aggravated with hip movements.


Diagnosis of piriformis syndrome:

The clinical symptoms of people with piriformis syndrome are sometimes similar to actual sciatica due to a vertebral disc herniation, but no abnormalities are seen in patient's MRI image. About six percent of people diagnosed with sciatica actually have piriformis syndrome.


Treatment of piriformis syndrome:

Treatment for piriformis syndrome includes the following:

  • Stop activities that start and intensify pain
  • Taking rest and avoiding heavy exercises
  • Heating the pain location
  • Analgesics and anti-inflammatory drugs
  • Start standard stretching exercises after the acute phase of pain


piriformis muscle


share this content in :
Address: 393 University Avenue,Suite 200,Toronto ON MG5 2M2,CANADA

Email: info@MarsoClinic.com

Phone: 1(647)303 0740

All Rights Reserved � By MarsoClinic

Terms of Use