Sciatica causes pain that travels from your lower back or buttock down the back of one leg, often reaching the calf or foot. If your pain follows that path and gets worse when you sit, bend forward, or raise your leg while lying down, there’s a good chance you’re dealing with it. About 70% of people with acute sciatica see a major reduction in pain within four weeks without any special treatment, so knowing what you’re feeling and when to take it seriously matters more than rushing to get an MRI.
What Sciatica Actually Feels Like
The sciatic nerve is the longest nerve in your body, running from your lower spine through your buttock and down each leg. When something presses on it, usually a bulging disc in your lower spine, pain radiates along the nerve’s path. That’s the hallmark: pain that travels. A pulled muscle or joint problem tends to stay in one spot. Sciatica moves.
The exact location of your symptoms depends on which nerve root is compressed. If the compression is higher up (around the L4 vertebra), you’ll feel pain along the inner leg and the top of your foot, possibly into your big toe. If it’s at L5, the pain runs down the outer calf to the top of the foot and the first three toes. If it’s at S1, the pain shoots down the entire back of your leg, from buttock to calf. Most people feel it on only one side.
The pain itself varies. Some people describe a sharp, burning sensation. Others feel a deep ache or an electric jolt that worsens with certain movements. Numbness, tingling, or a pins-and-needles feeling in the leg or foot is common. Some people say the affected leg feels heavy or weak, especially when trying to lift the foot or push off while walking.
A Simple Test You Can Try at Home
The straight leg raise is one of the first things a doctor will do to check for sciatica, and you can try a version of it yourself. Lie flat on your back on a firm surface. Keeping your knee completely straight, slowly raise the affected leg. If this reproduces your usual pain in your back or leg before your leg reaches about 60 degrees (roughly two-thirds of the way to vertical), that’s a strong indicator of nerve compression from a disc problem.
This test is more reliable in younger people. In patients over 60, it catches only about a third of confirmed disc herniations because the nature of spinal compression changes with age. A negative result doesn’t rule sciatica out, especially if you’re older. But if raising your leg clearly triggers that shooting pain down your leg, it’s a useful clue.
Sciatica vs. Piriformis Syndrome
Not all pain down the back of your leg comes from the spine. The piriformis is a small muscle deep in your buttock, and when it tightens or spasms, it can squeeze the sciatic nerve right where it passes underneath. This produces pain that feels a lot like sciatica but has a different source and different triggers.
A few differences can help you tell them apart. Piriformis syndrome typically causes deep buttock pain that worsens with hip movements, like crossing your legs, rotating your hip, or sitting for long periods. Lower back pain is less common with piriformis syndrome than with true spinal sciatica. If your pain is centered in your buttock and flares with hip rotation rather than bending forward or raising your leg, piriformis syndrome is more likely. True sciatica tends to involve more obvious back pain and that characteristic reproduction of symptoms during the straight leg raise.
Signs That Need Immediate Attention
Most sciatica is painful but not dangerous. There is one rare complication, however, that requires emergency care: cauda equina syndrome. This happens when a large disc herniation or other problem compresses the bundle of nerves at the base of your spinal cord all at once. It affects roughly 1 in 33,000 to 100,000 people, but missing it can lead to permanent damage.
Go to an emergency room if you develop any of these symptoms alongside your leg pain:
- Numbness in your inner thighs, buttocks, or groin (sometimes called “saddle” numbness because it affects the area that would touch a saddle)
- Difficulty controlling your bladder or bowels, including not being able to feel when you need to go, inability to urinate, or new incontinence
- Rapidly worsening weakness in one or both legs, especially if it’s progressing over hours or days
These symptoms together suggest the nerve bundle is being compressed in a way that requires urgent imaging and, often, surgery within 24 to 48 hours to prevent permanent loss of function.
When You Need an MRI (and When You Don’t)
If you go to a doctor with new sciatica symptoms and no red flags, you probably won’t get imaging right away. The American College of Radiology’s guidelines are clear: for back and leg pain lasting less than four weeks, with no alarming neurological symptoms, imaging provides no clinical benefit. Numerous studies confirm that routine scans in this window don’t improve outcomes. The reason is simple. Many people have disc bulges on MRI that cause no symptoms at all, so early imaging often muddies the picture rather than clarifying it.
Imaging becomes appropriate if your symptoms persist or worsen after six weeks of conservative treatment (things like staying active, physical therapy, and over-the-counter pain relief) and you’re being considered for an injection or surgery. At that point, an MRI of the lumbar spine without contrast is the standard first choice. It shows soft tissue, disc position, and the space around your nerves in detail that X-rays can’t match.
The exceptions are those red flag scenarios: suspected cauda equina syndrome, progressive leg weakness, a history of cancer, unexplained weight loss, recent significant trauma, or signs of infection. Any of these warrants imaging sooner.
What Recovery Typically Looks Like
Sciatica resolves on its own more often than most people expect. In a study of 214 patients with acute sciatica treated with a week of rest followed by gradual return to activity and simple pain relief, average leg pain scores dropped from 54 out of 100 to 19 within four weeks. Seventy percent reported a major reduction in both back and leg pain with improved function in that same timeframe, and 60% had returned to work.
The first few days are often the worst. Staying in bed for more than a day or two tends to slow recovery rather than help it. Gentle movement, walking, and avoiding positions that worsen the pain (prolonged sitting is a common trigger) generally work better than strict rest. Physical therapy focused on core stability and nerve mobility can speed things along. Most people improve steadily over four to six weeks, though some residual symptoms can linger for several months before fully clearing.
Muscle weakness is worth paying closer attention to. If you notice your foot slapping the ground when you walk, or you can’t lift your toes or push up on your tiptoes, that suggests the nerve is being compressed enough to affect motor function. This doesn’t always require surgery, but it does warrant a medical evaluation sooner rather than later, because prolonged nerve compression can lead to slower or incomplete recovery of strength.