The sciatic nerve is the major nerve supplying the lower back and legs of the body. It travels from the lower spine, through the pelvis, and down each leg. It is the longest and widest nerve. The sciatic nerve primarily supplies the muscles of the lower leg, including the calf, ankle and the back of the knee. It also supplies sensation to the sole of the foot, the ankle, the entirety of the lower leg, and the back of the thigh. The sciatic nerve branches into different parts of the body along its length, hence its ability to supply such a large area of the body. It is a mixed-function nerve, meaning that it contains both sensory neurons and motor neurons. This means that it simultaneously enables muscles to feel and move. Damage to the sciatic nerve can result in numerous symptoms, including lower back pain, muscle weakness and reflex abnormalities. Although it can be damaged anywhere, symptoms are usually present in the lower leg, such as an inability to bend the knee, an absence of ankle reflexes, or difficulty in rotating and bending the foot.
Written and medically reviewed by the Healthline Editorial Team
In Depth: Sciatic nerve