Piriformis muscle
You don't need to be Editor-In-Chief to add or edit content to WikiDoc. You can begin to add to or edit text on this WikiDoc page by clicking on the edit button at the top of this page. Next enter or edit the information that you would like to appear here. Once you are done editing, scroll down and click the Save page button at the bottom of the page.
| Piriformis muscle | |
|---|---|
| The piriformis and nearby muscles | |
| Muscles of the gluteal and posterior femoral regions, piriformis labeled | |
| Latin | musculus piriformis |
| Gray's | subject #128 476 |
| Origin | sacrum |
| Insertion | greater trochanter |
| Artery: | Inferior gluteal artery , Lateral sacral artery, Superior gluteal artery, |
| Nerve: | nerve to the Piriformis (L5, S1, and S2 nerve roots) |
| Action: | rotate laterally (outward) the thigh |
| Dorlands /Elsevier | m_22/12550205 |
The piriformis (from Latin piriformis = "pear shaped") is a muscle in the gluteal region of the lower limb.
Contents |
Origin and insertion
It originates from the anterior (front) part of the sacrum, the part of the spine in the gluteal region, and from the superior margin of the greater sciatic notch (as well as the sacro-iliac joint capsule and the sacrotuberous ligament).
It exits the pelvis through the greater sciatic foramen to insert on the greater trochanter of the femur.
Its tendon often joins with the tendons of the superior gemellus, inferior gemellus, and obturator internus muscles prior to insertion.
Shape and location
The piriformis is a flat muscle, pyramidal in shape, lying almost parallel with the posterior margin of the gluteus medius.
It is situated partly within the pelvis against its posterior wall, and partly at the back of the hip-joint.
It arises from the front of the sacrum by three fleshy digitations, attached to the portions of bone between the first, second, third, and fourth anterior sacral foramina, and to the grooves leading from the foramina: a few fibers also arise from the margin of the greater sciatic foramen, and from the anterior surface of the sacrotuberous ligament.
The muscle passes out of the pelvis through the greater sciatic foramen, the upper part of which it fills, and is inserted by a rounded tendon into the upper border of the greater trochanter behind, but often partly blended with, the common tendon of the obturator internus and gemelli.
Variations
It is frequently pierced by the common peroneal nerve (fibular) when the sciatic nerve bifurcates prior to exiting the greater sciatic foramen. Thus the Piriformis is divided more or less into two parts.
It may be united with the gluteus medius, or send fibers to the gluteus minimus or receive fibers from the superior gemellus.
It may have only one or two sacral attachments or be inserted in to the capsule of the hip-joint.
It may be absent.
Clinicals
This syndrome occurs when the piriformis irritates the sciatic nerve, which comes into the gluteal region beneath the muscle, causing pain in the buttocks and referred pain along the sciatic nerve. This referred pain is known as "sciatica." 15% of the population has their sciatic nerve coursing through the piriformis muscle. This subgroup of the population is predisposed to developing sciatica.
Additional images
 Sacrum, pelvic surface. |
 Upper extremity of right femur viewed from behind and above. |
 Right femur. Anterior surface. |
 Structures surrounding right hip-joint. |
 Left Levator ani from within. |
 The arteries of the gluteal and posterior femoral regions. |
 Dissection of side wall of pelvis showing sacral and pudendal plexuses. |
 Nerves of the right lower extremity Posterior view. |
External links
- SUNY Labs 13:st-0408 - "Gluteal Region: Muscles"
- SUNY Labs 43:15-0101 - "The Female Pelvis: The Posterolateral Pelvic Wall"
- -1281753008 at GPnotebook
- LUC pirf
- - "Piriformis Muscle Stretch, Biomechanics & Piriformis-Sciatic Nerve Relationship Graphics
References
This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.
de:Musculus piriformisit:PiriformeAcknowledgement and Attribution Regarding Sources of Content
Some of the initial content on this page may be incorporated in part from copyleft sources in the public domain including wikis such as Wikipedia and AskDrWiki. Drug information for patients came from the The National Library of Medicine. Infectious disease information may have come from the Centers for Disease Control (CDC). Differential Diagnoses are drawn from clinicians as well as an amalgamation of 3 sources: 1.The Disease Database; 2. Kahan, Scott, Smith, Ellen G. In A Page: Signs and Symptoms. Malden, Massachusetts: Blackwell Publishing, 2004:3; 3. Sailer, Christian, Wasner, Susanne. Differential Diagnosis Pocket. Hermosa Beach, CA: Borm Bruckmeir Publishing LLC, 2002:7 .
