The lumbosacral trunk, which consists of a portion of the spinal nerves L4 and L5, and the ventral rami S1 to S3 unite on the anterior surface of the piriformis muscle to form the sacral plexus[^1]. The sacral plexus is also combined with the lumbar plexus into the lumbosacral plexus.

Anatomy

The following peripheral nerves emerge from the sacral plexus:

Superior gluteal nerve
Inferior gluteal nerve
Posterior cutaneous nerve of the thigh
Sciatic nerve
Pudendal nerve

Illustration

Sacral plexus — Schematic illustration of the sacral plexus. Illustration adapted from Grays Anatomy Illustration No. 828.

Sacral plexus

Anatomy

Illustration