It usually starts as a deep ache in the buttock that you can't quite stretch out. Then it starts traveling — a burning, shooting, electric pain down the back of the thigh, sometimes all the way to the calf or foot. That traveling leg pain has a name: sciatica. As specialists we call it lumbar radiculopathy — radiculopathy is the medical term for a nerve root that is compressed or irritated. And the first thing to understand is that sciatica isn't a diagnosis. It's a symptom — your body's way of saying a nerve is being pinched somewhere along its path.
What sciatica actually is
The sciatic nerve is the largest nerve in the body, formed from nerve roots exiting the lower spine (roughly L4 through S3) that join into one thick cable running through the buttock and down the leg. When one of those roots gets compressed or irritated, the brain feels the pain along the nerve's territory — which is why the problem is in your back but the pain is in your leg. True sciatica is almost always one-sided; pain in both legs simultaneously points toward a different problem, like spinal stenosis.
The usual suspects
By far the most common cause is a herniated lumbar disc — the soft inner disc material pushes out and presses directly on a nerve root. Less common causes include spinal stenosis narrowing the nerve's tunnel, a spondylolisthesis shifting a vertebra, and piriformis syndrome, where a small buttock muscle irritates the nerve (far less common than the internet suggests, but real). The treatment differs for each, which is why the diagnosis has to come before the plan.
Sciatica vs. its look-alikes
Not all leg pain is sciatica, and the mimics matter. Hip arthritis refers pain to the groin and front of the thigh — rarely below the knee. SI joint dysfunction usually aches in the buttock, though it can send pain down the leg in what we call pseudoradiculopathy — mimicking sciatica without any actual nerve compression. Piriformis syndrome can mimic sciatica closely, but true piriformis cases are uncommon and the exam pattern differs. Vascular claudication — poor circulation — cramps the calves with walking and eases with rest alone, no position change needed. Sorting these out is exactly what the history and physical exam are for: same complaint, different diseases, different treatments.
How it's diagnosed
The story matters enormously: pain that worsens with sitting, coughing, or sneezing and eases when you change position is classic for a disc irritating a nerve. On exam, the straight-leg raise test — lifting your extended leg reproduces the shooting pain — is a classic bedside finding pointing to nerve root irritation. MRI then confirms the culprit, but with the same rule as always: the image has to match the person. Plenty of painless spines have bulging discs.
Red flags worth knowing
Most sciatica is painful but not dangerous. The exceptions need prompt attention: progressive weakness (a foot that starts slapping when you walk), numbness in the saddle area, or any change in bladder or bowel function. Severe, unrelenting night pain that nothing eases also deserves a timely workup. These are uncommon, but they're the reason I list them in every sciatica conversation.
What actually helps
Here's what surprises people: bed rest makes sciatica worse, not better. Staying gently active — short walks, avoiding prolonged sitting — beats lying still. Targeted physical therapy — extension-based (McKenzie) exercises help many disc-related cases by centralizing the pain, moving it out of the leg and back toward the spine, which is the direction of healing — anti-inflammatories, and time resolve the majority of cases within 6 to 12 weeks; the body's own cleanup crew gradually reabsorbs much herniated disc material. An epidural steroid injection can calm an angry nerve root and buy comfortable time while that happens.
When surgery enters the picture
Surgery earns its place in three situations: progressive weakness, pain that remains severe despite a good trial of conservative care, or simply a patient whose life is on hold and who understands the trade-offs. A microdiscectomy removes the fragment pressing the nerve through a small incision — and the classic result is leg pain that's dramatically better the moment you wake up. It doesn't fix backs in general; it fixes the specific pinched nerve. Matched to the right diagnosis, it's one of the most gratifying operations in spine surgery.