Piriformis
Original Editor - Lucas Villalta
Top Contributors - Lucas Villalta, Vidya Acharya, Kim Jackson, Candace Goh, 127.0.0.1, Laura Ritchie, Evan Thomas, WikiSysop and Wendy Snyders;
Description
Piriformis is a flat muscle and the most superficial muscle of the deep gluteal muscles. It is part of the lateral rotators of the hip (obturator internus, superior and inferior gemelli, quadratus femoris, obturator externus, and gluteus maximus). It leaves the pelvis through the greater sciatic notch, until its fixation reaches the superior margin of the greater trochanter.[1] It has a piramidal shape that lies almost parallel with the posterior margin of the gluteus medius.
Anatomy
Origin[1]
- Anterior aspect of the sacrum at the level of about S2 through S4
- Sacrotuberous ligament
- Periphery of the greater sciatic notch
Insertion[1]
- Superior and medial aspects of the greater trochanter
Nerve[1]
- Ventral rami of L5 and S1,2
Artery[3]
- Inferior gluteal artery, the lateral sacral artery, internal pudendal and the superior gluteal artery
Function[1][4]
- Lateral Rotation of the hip when it is extended;
- Abduction fo the hip when it is flexed.
Clinical relevance
The piriformis muscle can be used to locate the scietic nerve. This nerve enters the gluteal region inferiorly to the piriformis.If the lateral rotators of the hip are tight they may exert pressure on the sciatic nerve, producing pain radiating into the lower extremity.[1][5] This is known as Piriformis Syndrome.
Another importance of this muscle is that it divides the gluteal region into a superior and inferior part. Therefore, it determines the name of the vessels anf nerves that supply the area (e.g. the superior gluteal nerve and vessels emerge superiorly to the piriformis, and the inferior gluteal nerve and vessels emerge inferiorly to the piriformis).[5]
Assessment
Palpation
It may be palpable indirectly through the gluteus maximus into the greater scietic notch.
Test
Treatment
Strengthening
Stretching
Manual techniques
Recent Related Research (from Pubmed)
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Oatis, C. A., (2009). Kinesiology : the mechanics and pathomechanics of human movement (2nd ed). Baltimore : Lippincott Williams & Wilkins.
- ↑ Michael Forrester. 201603 Visual Anatomy of the Hips Part 5 Lateral Hip Rotation Piriformis and more. Available from: https://www.youtube.com/watch?v=nq00pUMKlQo
- ↑ http://lowerlimbanatomy.wikispaces.com/Piriformis
- ↑ Moore, K. L., Dalley, A. F., Agur, A. M. R. (2014). Clinically oriented anatomy (7th ed).Philadelphia : Lippincott Williams & Wilkins.
- ↑ 5.0 5.1 http://teachmeanatomy.info/lower-limb/muscles/gluteal-region/