What might cause back pain that shoots down both legs?

Reviewed by Yoshinori Abe, MD

Internal Medicine

Bilateral sciatica—back pain that shoots down both legs—is most often caused by nerve compression in the lower spine. Common culprits include herniated discs, spinal stenosis, or degenerative disc disease pressing on the sciatic nerve roots. In rare cases, it may signal cauda equina syndrome, a medical emergency requiring immediate care, especially if accompanied by numbness in the groin or loss of bladder or bowel control.

Because pain radiating down both legs can stem from many conditions—some minor, some serious—identifying the underlying cause early leads to faster relief and better outcomes. Take a free, instant, online symptom check to better understand your symptoms and confidently plan your next steps.

Reviewed for medical accuracy: 07/14/2026

Important Next Steps

Learn likely causes of both-leg back pain Discover if your back pain needs care See if it could be a nerve issue Find OTC relief for back pain symptoms Find a doctor for back pain evaluation Understand medically proven back pain home remedies Check what’s causing your back and leg pain

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Explanation

Back pain that travels down the legs is often linked to nerve problems in the lower back. One common cause is sciatica, which happens when the sciatic nerve is irritated or compressed. This nerve runs from the lower back through the hips and down each leg.

Causes of Sciatica:

Herniated Disc: A disc in the spine can bulge out and press on the nerve.
Spinal Stenosis: This is when the spaces in the spine become narrow and squeeze the nerves.
Bone Spurs: These are extra bits of bone that can press on nerves.

Sometimes, severe cases of back pain that affect both legs may be related to a rare condition called cauda equina syndrome. This is a more serious problem where nerves at the end of the spinal cord get compressed, and it needs emergent medical help. If you have back pain with other symptoms like trouble urinating, or numbness around the anus, it is important to see a doctor right away. To help identify what might be causing your symptoms, you can use this free symptom checker before speaking with a healthcare professional for the right diagnosis and treatment.

(References)

Valat JP, Genevay S, Marty M, Rozenberg S, & Koes B. (2010). Sciatica. Best practice & research. Clinical rheumatology, 20227645.
Govind J. (2004). Lumbar radicular pain. Australian family physician, 15253601.
Polsky Z, Greidanus M, Pandya A, & Jacobs WB. (2020). Risk stratifying nontraumatic back pain for Cauda Equina .... CJEM, 32519628.

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