What You Need to Know About Sciatica

The term sciatica describes the symptoms of leg pain—and possibly tingling, numbness or weakness—that originate in the lower back and travel through the buttock and down the large sciatic nerve in the back of the leg.

Watch: Sciatica Animated Video

Sciatica (pronounced sigh-at-ih-kah) is not a medical diagnosis in and of itself—it is a symptom of an underlying medical condition, such as a lumbar herniated disc,degenerative disc disease, or spinal stenosis.

Sciatica Nerve Pain

Sciatica is often characterized by one or a combination of the following symptoms:

• Constant pain in only one side of the buttock or leg (rarely can occur in both legs)
• Pain that is worse when sitting
• Leg pain that is often described as burning, tingling or searing (vs. a dull ache)
• Weakness, numbness or difficulty moving the leg or foot
• A sharp pain that may make it difficult to stand up or to walk

Watch: Sciatica Causes and Treatments Video

Sciatic pain can vary from infrequent and irritating to constant and incapacitating. Specific sciatica symptoms can be different in location and severity, depending upon the condition causing the sciatica (such as alumbar herniated disc ).

While symptoms can be painful and potentially debilitating, it is rare that permanent sciatic nerve damage (tissue damage) will result.

• See Sciatica Symptoms

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Learn how what happens to the sciatic nerve to cause sciatica. 
Watch: Sciatic Nerve Anatomy Video

The Sciatic Nerve and Sciatica

Sciatica symptoms occur when the large sciatic nerve is irritated or compressed in the lumbar spine.

The sciatic nerve is the largest single nerve in the body and is composed of individual nerve roots that start by branching out from the spine in the lower back and combine to form the "sciatic nerve."

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• The sciatic nerve starts in the lower back at lumbar segment 3 (L3).
• At each level of the lower spine a nerve root exits from the inside of the spine, and these respective nerve roots then come together to form the large sciatic nerve.
• The sciatic nerve runs from the lower back, through the buttock, and down the back of each leg
• Portions of the sciatic nerve then branch out in each leg to innervate certain parts of the leg - the thigh, calf, foot, toes.

The specific sciatica symptoms - the leg pain, numbness, tingling, weakness, and possibly symptoms that radiate into the foot - largely depend on where the nerve is pinched. For example, a lumbar segment 5 (L5) nerve impingement can cause weakness in extension of the big toe and potentially in the ankle.