A sciatic nerve diagram is a diagram displaying the sciatic nerve in relation to other parts of the body. The sciatic nerve begins in the lower back and runs down the length of the entire leg. It is both the longest and widest nerve in the body.
The sciatic nerve is responsible for controlling almost the entirety of the lower back and the leg. When this nerve is compressed or irritated, a painful condition called sciatica can result. Sciatica can make it difficult or painful to bend at the knee although it can affect other parts of the lower back and upper leg. Spinal disc herniation is a common cause of sciatica as is degenerative disc disease.