The nerve to quadratus femoris is a nerve

Nerve

A peripheral nerve, or simply nerve, is an enclosed, cable-like bundle of peripheral axons . A nerve provides a common pathway for the electrochemical nerve impulses that are transmitted along each of the axons. Nerves are found only in the peripheral nervous system...

 that provides innervation to the quadratus femoris and gemellus inferior muscles.

Course

The nerve to quadratus femoris is a sacral plexus

Sacral plexus

-External links:*...

 nerve. It arises from the ventral divisions of the fourth and fifth lumbar and first sacral nerves: it leaves the pelvis

Pelvis

In human anatomy, the pelvis is the lower part of the trunk, between the abdomen and the lower limbs .The pelvis includes several structures:...

 through the greater sciatic foramen

Greater sciatic foramen

-Boundaries:It is bounded as follows:* anterolaterally by the greater sciatic notch of the illium* posteromedially by the sacrotuberous ligament* inferiorly by the sacrospinous ligament and the ischial spine* superiorly by the anterior sacroilliac ligament...

, below the piriformis muscle, and runs down in front of the sciatic nerve

Sciatic nerve

The sciatic nerve is a large nerve fiber in humans and other animals. It begins in the lower back and runs through the buttock and down the lower limb...

, the superior

Superior gemellus muscle

The superior gemellus muscle is a muscle of the human body.The Gemelli are two small muscular fasciculi, accessories to the tendon of the Obturator internus which is received into a groove between them....

 and inferior gemellus muscle

Inferior gemellus muscle

The inferior gemellus muscle is a muscle of the human body.The Gemelli are two small muscular fasciculi, accessories to the tendon of the Obturator internus which is received into a groove between them....

s, and the tendon of the obturator internus, and enters the anterior surfaces of the muscles; it gives an articular branch to the hip-joint.