The sciatic nerve is the largest and longest nerve in the human body. It originates from the lower spine, specifically from the nerve roots L4 to S3 in the lumbosacral plexus, which is located just outside the base of the spine in the lumbar and sacral regions
. From its origin, the sciatic nerve passes through the pelvis via the greater sciatic foramen, emerging below the piriformis muscle in the buttock area
. It then travels deep in the buttock, running beneath and along the side of the gluteus maximus muscle
. The nerve continues down the back of the thigh, lying deep to the large thigh muscle called the biceps femoris, and runs down the posterior compartment of the thigh
. At the level of the knee (popliteal fossa), the sciatic nerve divides into two main branches: the tibial nerve and the common fibular (peroneal) nerve, which continue down into the lower leg and foot
. In summary, the sciatic nerve is located:
- Origin: Lower back (lumbar and sacral spine, L4-S3)
- Course: Through the pelvis (greater sciatic foramen), deep in the buttock below the piriformis muscle
- Down the back of the thigh, deep to the biceps femoris muscle
- Splits near the knee into tibial and common fibular nerves
It extends from the lower back, through the buttocks, and down the back of each leg to the foot
