What is sciatica?

Return to Index Step 1: What Is Low Back Pain?Step 2: Know Your Back Anatomy Step 3: Causes of Low Back Pain Step 4: Are You At Risk?Step 5: What To Do When Pain Begins Step 6: Seeing Your Doctor Step 7: What Tests Might Be Ordered?Step 8: When Is Low Back Pain A Serious Sign?Step 9: Exercise and Physical Therapy Step 10: Change Your Work Habits Step 11: Medications Step 12: Other Treatments Key Points MedTest Glossary

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What is sciatica?

Sciatica is pain that runs along your leg and often accompanies low back pain. The sciatic nerve is a large nerve (as wide as your thumb) that is made up of branches from the lowest part of the spinal cord (the lumbar and sacral areas -- see step 2). The nerve travels through the pelvis, deep below the buttocks, passing down the hip and along the back of the thigh all the way to your foot.

If the sciatic nerve gets trapped or inflamed anywhere along this route, you may feel pain. This is called sciatica. There are several ways that a low back injury may press on the sciatic nerve and cause sciatica. Two common reasons are a herniated disk and spinal stenosis (narrowing of the spinal canal).

Sciatica can also result from a sudden injury. For example, if a buttocks muscle is injured from running too hard or lifting too many weights, it may swell or tighten and put pressure on the sciatic nerve causing pain.

Sciatica causes pain anywhere along the route that the sciatic nerve travels (your buttocks, the back of your thigh, the back of your calf, and even your foot). The sensation may be only a slight tingling or dull ache or it may be severe enough to decrease your ability to move. Sciatica almost always affects one leg or the other. Sometimes, however, you may have symptoms in both legs.

Review Date: 7/29/2011
Reviewed By: Andrew W. Piasecki, MD, Camden Bone and Joint, LLC, Orthopaedic Surgery/Sports Medicine, Camden, SC. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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