Sciatica produces pain that travels from your lower back or buttock down the back of one leg, often reaching below the knee and sometimes into the foot. The defining feature is this radiating pattern: pain that follows a path rather than staying in one spot. If your pain stays only in your lower back or only in your buttock without traveling down the leg, it’s probably something else.
Where the Pain Shows Up
The sciatic nerve is the longest nerve in your body, running from the lower spine through the buttock and down the entire back of each leg. When it gets compressed or irritated, usually by a herniated disc or narrowing of the spinal canal, the pain follows that same route. It typically starts in the lower back or deep in the buttock and travels through the back of the thigh and calf. Some people feel it all the way into the foot or big toe.
Sciatica almost always affects only one side. If both legs hurt simultaneously, that’s unusual enough to warrant prompt medical evaluation.
What Sciatica Feels Like
The sensation varies quite a bit from person to person, and it can even shift throughout the day. Some people describe a deep, burning ache. Others feel a sharp jolt or electric shock that shoots down the leg. You might experience numbness, tingling, or a pins-and-needles sensation alongside the pain, and it’s common for one part of the leg to hurt while another part feels numb.
Muscle weakness is another telltale sign. Depending on which nerve root is compressed, you might have trouble walking on your toes, lifting your foot upward, or notice that your leg feels unreliable when climbing stairs. A foot that slaps the ground when you walk, sometimes called foot drop, points toward compression higher up in the nerve pathway.
The pain tends to get worse with certain movements and positions. Coughing, sneezing, and bending forward are classic triggers because they increase pressure on the spinal discs. Sitting for long stretches often makes things worse, while lying down or walking gently may bring some relief. If raising your leg while lying on your back reproduces the shooting pain, that’s a strong indicator.
A Simple Self-Check
Doctors use a test called the straight leg raise to screen for sciatica, and you can get a rough idea at home. Lie flat on your back and have someone slowly lift your affected leg, keeping the knee straight. If pain shoots down your leg past the knee when the leg reaches somewhere between 30 and 70 degrees off the ground, that’s a positive result. Pain only in the lower back, tightness in the hamstring, or general discomfort without that radiating quality doesn’t count.
You can also try a seated version: sit on the edge of a chair or bed with your back upright and slowly straighten the knee of your affected leg. If this reproduces the familiar shooting pain below the knee, it suggests the sciatic nerve is being stretched against something it shouldn’t be.
These tests are useful screening tools, but they’re not definitive on their own. The straight leg raise is quite sensitive, catching about 91% of true sciatica cases, but it also flags many people who don’t actually have it. A doctor can combine this with a neurological exam checking your reflexes, sensation, and muscle strength to narrow things down more precisely.
Sciatica vs. Piriformis Syndrome
Piriformis syndrome is the condition most commonly confused with sciatica because it involves the same nerve. The piriformis is a small muscle deep in the buttock that the sciatic nerve runs through or next to. When this muscle tightens or spasms, it can squeeze the nerve and mimic sciatica. A few differences help separate the two.
With piriformis syndrome, pain usually originates deep in the buttock rather than in the lower back, and it rarely extends below the knee. Pressing on the center of the buttock often reproduces a specific, localized tenderness. The pain worsens with hip rotation activities like getting out of a car, crossing your legs, or climbing stairs. True sciatica, by contrast, starts in the lower back, frequently radiates all the way to the foot, and flares with spinal movements like bending forward, prolonged standing, or sneezing.
When Imaging Comes Into Play
If you suspect sciatica, you might expect to need an MRI right away. Medical guidelines say otherwise. For pain that’s been present less than four weeks with no alarming neurological symptoms, imaging typically isn’t recommended because most cases improve on their own. An acute episode usually resolves within one to two weeks, and most people feel significantly better within a few weeks without any procedure.
An MRI becomes appropriate after about six weeks of persistent or worsening symptoms, particularly if you and your doctor are considering more targeted treatments or surgery. The reason for waiting isn’t neglect. Disc herniations commonly show up on MRI in people with zero symptoms, so early imaging can create more confusion than clarity.
Symptoms That Need Emergency Attention
A rare but serious complication called cauda equina syndrome occurs when the bundle of nerves at the base of the spine gets severely compressed. This is a surgical emergency. The warning signs include sudden difficulty urinating or having a bowel movement, loss of sensation in the inner thighs, groin, or buttocks (sometimes called saddle numbness), and rapidly worsening weakness in one or both legs. If you develop any combination of these symptoms alongside back or leg pain, go to an emergency room immediately. Delays in treatment can lead to permanent nerve damage.
Putting the Clues Together
No single symptom confirms sciatica. The diagnosis comes from a pattern: pain that radiates from the lower back or buttock down the back of one leg, possibly accompanied by numbness, tingling, or weakness, and worsened by coughing, sneezing, or bending. The more of these features you recognize, the more likely sciatica is the explanation. If the pain stays above the knee, doesn’t radiate, or affects both sides equally, other causes are worth exploring with a healthcare provider.