The piriformis
Piriformis · musculus piriformis
A pear-shaped deep buttock muscle that sits right next to the sciatic nerve.
What it does
The piriformis runs from the front of the sacrum, out through a gap in the pelvis, to the top of the femur. It rotates the thigh outwards and steadies the hip. The sciatic nerve passes just below it, and in some people straight through it.
Surprising fact
In a minority of people, part or all of the sciatic nerve runs through the middle of the piriformis instead of beneath it.
Why it matters
A tight or irritated piriformis can press on the sciatic nerve and cause buttock pain that runs down the leg, sometimes called piriformis syndrome.
Nearby
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Sources
Drafted with AI help; awaiting a human fact-check against these sources.
Open in the 3D atlas · Suggest a correction · Not medical advice.
3D models: Z-Anatomy & BodyParts3D (CC BY-SA 4.0 / 2.1 JP). Card text CC BY 4.0.