The sciatic nerve, the longest and widest single nerve in the human body, begins in the lower back and runs through the buttock and down the lower limb.
The sciatic nerve provides the connection to the nervous system for nearly the whole of the skin of the leg, the muscles of the back of the thigh, and those of the leg and foot.
It is formed from the L4 to S3 segments of the sacral plexus, a collection of nerve fibres that emerge from the sacral part of the spinal cord.
The fibres unite to form a single nerve in front of the piriformis muscle.
The nerve passes beneath piriformis and through the greater sciatic foramen, exiting the pelvis.
From here, it travels down the posterior thigh to the popliteal fossa.
The nerve travels in the posterior compartment of the thigh behind (superficial to) the adductor magnus muscle, and in front of (deep to) one head of the biceps femoris muscle.
At the popliteal fossa, the nerve divides into its two branches:
- The tibial nerve, which travels down the posterior compartment of the leg into the foot
- The common peroneal nerve (also called the common fibular nerve), which travels down the anterior and lateral compartments of the leg into the foot
Keyword: sciatic nerve distribution