Piriformis

**Author: Zeenath Higgins** toc =Description = The piriformis muscle is located in the gluteal region of the lower limb. It is located partly within the pelvis against its posterior wall, and partly at the back of the hip-joint. This muscle is a flat muscle, it is pyramidal in shape (pear shaped), and it lies parallel to the posterior region of the gluteus medius. The piriformis muscle originates from the anterior part of the sacrum (which is also known as the tailbone); the origins arise from the superior margin of the greater sciatic notch, as well as the sacroiliac joint capsule and the sacrotuberous ligament. The muscle travels laterally and inferiorly to exit through the greater sciatic foramen of the pelvis and insert on the medial side of the superior border of the greater trochanter of the femur. The tendon of the piriformis muscle often joins with the tendons of the gemellus superior, gemellus inferior, and obturator internus muscles before insertion. The piriformis muscle is responsible for the action of lateral rotation. It is also responsible for abduction of the thigh if the hip joint is flexed. It is also very important for stabilising the hip joint and the pelvis. It is therefore also in action when you are standing on one leg or turning your trunk, standing on an unstable surface, when you are keeping your balance on a moving train or bus, when you are moving your leg outward and across to get out of a car and when you move across to another seat without standing up. The piriformis muscle receives its nerve supply from the nerve to the piriformis which arises from the sacral plexus roots L5, S1 and S2. Its blood supply is received from the inferior gluteal artery, the lateral sacral artery, internal pudendal and the superior gluteal artery.

=Interactions and relations to other Muscles = The piriformis is found in the gluteal region. It lies between the gluteus minimus and the gemellus superior. It is one of six deep lateral rotator muscles which are located on the gluteal region of the lower limb, the other five muscles being the quadratus femoris, the gemellus inferior, the obturator internus, obturator externus and the gemellus superior. As previously mentioned the tendon of the piriformis muscle often joins withthe tendons of the gemellus superior, gemellus inferior, and obturator internus muscles before its insertion on the medial side of the superior border of the greater trochanter of the femur, it is important to note that this fusion does not always occur. These five deep rotator muscles perform the action of lateral rotation of the hip joint along with the piriformis and are therefore considered synergists of the piriformis. The antagonistsof the piriformis in lateral rotation are the gluteus medius and the gluteus minimus. These antagonistic muscles make up part of the superficial layer and lie just above and next to the piriformis. These muscles are responsible for medial rotation of the hip joint. The piriformis also performs the action of abduction when the hip joint is flexed. The synergists in this case are the upper and middle fibers of the gluteus maximus, gluteus medius, gluteus minimus, tensor fasciae latae and sartorius. The antagonists for the muscle in this movement are the lower fibres of the gluteus maximus, the adductor magnus, the adductor longus, the adductor brevis, the gracilis, the pectineus, the psoas major and the iliacus, these muscles are responsible for hip adduction.

=Relevance to Physiotherapy: = Physiotherapists often treat the cases of piriformis syndrome. This condition includes symptoms of constant gluteal region and thigh pain, this is due to the fact that nerves near the piriformis muscle, usually the sciatic nerve, are pinched, causing irritation and pain that can sometimes be severe. Piriformis syndrome usually results from tightness in the muscle. In the first 48 to 72 hours the way that this syndrome is treated is with the R.I.C.E. concept, this abbreviation stands for resting the body, icing the gluteal region, compression of the gluteal region usually with an elastic bandage, elevation of the gluteal region, the patient is then finally refered to a doctor by the physiotherapist. In the final stages of piriformis syndrome, before patients return to sport they may be advised by the doctor to seek pre-sport massage this is another case where the physiotherapist would come in and massage the patient’s gluteal region, this keeps the muscle warm and also loosen the soft tissue in the gluteal region ready for stretching and exercise. The physiotherapist can also do stretches which can help and assist the muscle to loosen; this relieves the tightness which causes the pinched nerve. There is a link below showing a video on how to effectively stretch this muscle.

=Links to online interactive material: =

Pirifomis muscle anatomy
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How to stretch the piriformis muscle
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Piriformis syndrome
media type="custom" key="19687198" **References:**


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