Basic science · Interactive 3D

Sciatic nerve & short external rotators

The right hip from behind with gluteus maximus removed: piriformis, the gemelli, obturator internus and quadratus femoris, and the sciatic nerve leaving below piriformis and crossing them.

Interactive — drag to rotate

AI-assisted model. Labels checked against standard anatomy references; specialist review pending.

What to look at

1From above down the short external rotators are piriformis, superior gemellus, obturator internus, inferior gemellus and quadratus femoris.
2The sciatic nerve usually leaves the pelvis through the greater sciatic foramen below piriformis, then runs down superficial to the gemelli, obturator internus and quadratus femoris.
3In the posterior approach the rotators are divided close to the femur and reflected back over the nerve to protect it.
4The common peroneal division is the more lateral and more often injured — foot drop after hip surgery.

Hotspots

1Piriformis — Leaves the pelvis through the greater sciatic foramen; the key landmark of the gluteal region.
2Superior gemellus — From the ischial spine.
3Obturator internus — Exits through the lesser sciatic foramen and turns 90° round the ischium.
4Inferior gemellus — From the ischial tuberosity.
5Quadratus femoris — Lowest of the group; the medial femoral circumflex artery lies deep to it.
6Sciatic nerve — L4–S3; runs superficial to the short rotators below piriformis.
7Greater trochanter — The short rotators insert around its posterior surface and the trochanteric fossa.
8Sacrum — Piriformis arises from its anterior surface.

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