What is sciatica? Sciatica refers to a group of symptoms that occur when either sciatic nerve is compressed, injured or inflamed. The sciatic nerves are the longest nerves in the body. They branch out from the spinal cord in the lower back and run through the buttocks and down the legs. The sciatic nerves and their branches are responsible for both movement and sensation in the legs and feet. Compression, injury or inflammation of the sciatic nerve results in symptoms that typically include pain anywhere along the nerve path through the buttock, leg and foot on the affected side. Weakness and numbness can also occur. There can be marked variability in the specific combination of motor and sensory symptoms. A common cause of sciatic nerve compression and inflammation is a herniated, or bulging, disk in the lower spine. Sciatic nerve compression can also be due to general wear and tear on the spine and the disks that cushion the vertebrae of the spine. Sciatica is treatable. Treatment for sciatica varies depending on the severity of your symptoms, the presence of complications, your age and medical history, and the type of work and activities you perform. Seek prompt medical care if you experience symptoms of sciatica, such as pain that runs down the leg. Early diagnosis and treatment can reduce or eliminate symptoms and complications, such as loss of leg movement and disability. Seek immediate medical care (call 911) if you, or someone you are with, have loss of leg movement or sensation, or loss of bowel or bladder control (incontinence).