Piriformis at a glance
- What it is
- A pear-shaped lateral rotator of the hip that passes through the greater sciatic foramen.
- Location
- Originates from the anterior surface of the sacrum between the anterior sacral foramina and inserts onto the superior border of the greater trochanter of the femur.
- Function
- Laterally rotates the extended thigh and abducts the flexed thigh, and stabilizes the femoral head in the acetabulum.
- Body system
- Muscular · paired (left and right)
- FMA ID
- FMA22340 (Foundational Model of Anatomy)
Key facts
- Innervation: nerve to piriformis (S1–S2)
- Blood supply: superior and inferior gluteal arteries
- Key landmark dividing the suprapiriform and infrapiriform parts of the greater sciatic foramen
Clinical relevance
The sciatic nerve usually passes below it, and compression is implicated in piriformis syndrome.
Structures next to the piriformis
The nearest named structures in the 3D model, measured from the centre of each part:
- Gemellus superior · muscular
- Hip bone · skeletal
- Gluteus maximus · muscular
- Gluteus medius · muscular
- Gluteus minimus · muscular
- Gemellus inferior · muscular
- Obturator internus · muscular
- Iliacus · muscular
- Obturator vein · cardiovascular
- Superior gluteal vein · cardiovascular
References
- Foundational Model of Anatomy: Piriformis (FMA22340). EMBL-EBI Ontology Lookup Service.
- OpenStax. Anatomy and Physiology 2e, §11.2 Naming Skeletal Muscles. Rice University, 2022.
- Mitsuhashi N. et al. (2009). BodyParts3D: 3D structure database for anatomical concepts. Nucleic Acids Research 37, D782–D785. Data © The Database Center for Life Science, CC BY 4.0.
Related anatomy
Explore the whole body in the interactive 3D human anatomy model, or browse the A–Z list of human structures.