The sciatic nerve, which is as big as our thumb, is considered the largest and longest single nerve in the human body. It starts in the lower spine where nerve roots exist in the bone gaps in the spinal cord and extends to the back of the legs and all the way down the toes. The sciatic nerve enables leg sensation, strength, and reflexes. It also connects the spinal cord to other parts of our thighs, as well as the muscles in our lower leg and feet.
Anatomy of the sciatic nerve combination
From the combination of the fourth and fifth lumbar nerves and first three sacral spine nerves, the sciatic nerve is made up of five nerves that is located at the right and left hand side of our lower spine. Each nerve exits the spine between two vertebral segments. The L5 nerve root exits between lumbar segment 4 and 5 and the S1 nerve root exits between L5 and sacral segment 1. The S2 and S3 nerves, on the other hand, are the ones that emerge from the sacral foramen. The sciatic nerve is composed of the five nerves that is grouped together at the front of our piriformis muscle. Since the sciatic nerve travels down to the back of each leg, it enables motor and sensory functions to specific leg and foot regions.
The sciatic nerve is further divided into two nerves which innervates different parts of our lower leg:
These nerves travels sideways along the outer part of the knee and all the way down to the upper foot.
The tibial nerves travel downward to the feet and supply the nerves to our heels and the soles of our feet.
Depending on the affected nerve, symptoms may also occur at different parts of our leg and foot due to the different nerve pathways of the sciatica nerve. Radiating pain will occur if there is any problems in the lower spine that affect the sciatic nerve. If impaired, it will also cause muscle weakness, numbness, and a tingling sensation in legs, ankles, feet and toes.