Quick Facts
Origin: Sacral plexus (S1—S2).
Course: Passes directly from the sacral plexus into the piriformis muscle inside the pelvic cavity.
Branches: None.
Supply: Motor innervation to the piriformis muscle.
Related parts of the anatomy
Origin
The nerve to piriformis muscle is formed by the posterior divisions of the anterior rami of first and second sacral (S1-S2), and sometimes, the fifth lumbar nerves.
Course
Following its origin from the sacral plexus, the nerve passes directly into the piriformis muscle without leaving the pelvic cavity. The muscle lies on the anterior surface of the sacrum inside the true pelvis.
Branches
There are no named branches.
Supplied Structures
The nerve to piriformis provides motor innervation to piriformis muscle.
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Piriformis Muscle
The piriformis muscle arises as a series of segments on the deep surface of the sacrum and exits the sciatic notch to attach to the medial aspect of the greater trochanter.
