Pain that radiates from your lower (lumbar) spine to your buttock and down the back of your leg is the hallmark of sciatica. You might feel the discomfort almost anywhere along the nerve pathway, but it's especially likely to follow a path from your low back to your buttock and the back of your thigh and calf.

The pain can vary widely, from a mild ache to a sharp, burning sensation or excruciating pain. Sometimes it can feel like a jolt or electric shock. It can be worse when you cough or sneeze, and prolonged sitting can aggravate symptoms. Usually only one side of your body is affected.

Some people also have numbness, tingling or muscle weakness in the affected leg or foot. You might have pain in one part of your leg and numbness in another part.

Sciatica occurs when the sciatic nerve becomes pinched, usually by a herniated disk in your spine or by an overgrowth of bone (bone spur) on your vertebrae. More rarely, the nerve can be compressed by a tumor or damaged by a disease such as diabetes.

Risk factors for sciatica include:

• Age. Age-related changes in the spine, such as herniated disks and bone spurs, are the most common causes of sciatica.

• Obesity. By increasing the stress on your spine, excess body weight can contribute to the spinal changes that trigger sciatica.

• Occupation. A job that requires you to twist your back, carry heavy loads or drive a motor vehicle for long periods might play a role in sciatica, but there's no conclusive evidence of this link.

• Prolonged sitting. People who sit for prolonged periods or have a sedentary lifestyle are more likely to develop sciatica than active people are.

• Diabetes. This condition, which affects the way your body uses blood sugar, increases your risk of nerve damage.

Although most people recover fully from sciatica, often without treatment, sciatica can potentially cause permanent nerve damage. Seek immediate medical attention if you have:

• Loss of feeling in the affected leg

• Weakness in the affected leg

• Loss of bowel or bladder function