Piriformis nerve
# Piriformis nerve

The piriformis nerve, also known as the nerve to piriformis, is the peripheral nerve that provides motor innervation to the piriformis muscle.

## Structure

### Origin

The nerve to piriformis is a branch of the sacral plexus. It (typically) arises from the posterior divisions/branches of anterior rami of S1 and S2.

### Course

It enters the anterior surface of the piriformis muscle.

### Variation

Origin

It may sometimes arise from the anterior ramus of S2 only.

Number

It may be doubled. An additional branch may arise from the superior gluteal nerve.

### Distribution

The piriformis nerve innervates the piriformis muscle.

