What Causes Sciatic Nerve Pain? Symptoms, Duration & When It Spreads to the Knee and Hip

You’re reaching for something on the bottom shelf when it hits: a sharp, electric jolt that shoots from your lower back all the way down through your leg. It stops you mid-motion. For the millions of Americans who experience sciatic nerve pain each year, that moment is all too familiar.

Sciatic nerve pain is most commonly caused by a herniated disc pressing on the nerve roots in the lower spine. Other causes include spinal stenosis, piriformis syndrome, and spondylolisthesis. Most cases resolve within 4–6 weeks with appropriate care.

The sciatic nerve is the longest nerve in the human body. It runs from the lower back through the hips and buttocks and down each leg. When something compresses or irritates this nerve, the result is sciatica, a condition that can range from a dull ache to debilitating pain that disrupts daily life.

Sciatica is particularly common among working adults who sit for extended periods, people whose jobs require heavy lifting, and adults over the age of 50 who may be experiencing age-related spinal changes.

What Causes Sciatic Nerve Pain?

Understanding what causes sciatic nerve pain is the first step toward finding lasting relief. In most cases, the root cause is a structural issue in the lower spine that puts pressure on one or more nerve roots. Here are the most common causes our spine specialists see at Atlantic Brain and Spine.

Herniated or Slipped Disc

A herniated disc is the most common cause of sciatica, accounting for roughly 90% of cases. The spinal discs act as cushions between the vertebrae. When the soft inner material of a disc pushes through its outer layer, it can press directly on the nerve roots at the L4–L5 or L5–S1 levels. This is the exact point where the sciatic nerve originates.

Disc herniations can result from repetitive bending or lifting, prolonged sitting, or age-related wear. They are especially common in adults between the ages of 30 and 50.

Bone Spurs and Spinal Stenosis

Spinal stenosis refers to a narrowing of the spinal canal that compresses the nerves running through it. This condition becomes more common after age 50 as the spine undergoes degenerative changes. Bone spurs (bony overgrowths that form along the edges of the vertebrae) can contribute to this narrowing.

It’s important to understand the difference between central stenosis, where the main spinal canal narrows, and foraminal stenosis, where the nerve exit points become restricted. Both can produce sciatic symptoms, though they may require different treatment approaches.

Piriformis Syndrome

Piriformis syndrome is an often-overlooked cause of sciatic pain. The piriformis is a small muscle deep in the buttock that sits directly over the sciatic nerve. When this muscle becomes tight or inflamed from overuse, prolonged sitting, or injury, it can compress the nerve and produce symptoms that closely mimic disc-related sciatica.

One key difference: piriformis syndrome typically does not involve lower back pain. The discomfort tends to originate in the buttock and radiate down the leg.

Spondylolisthesis

Spondylolisthesis occurs when one vertebra slips forward over the one below it, pinching the sciatic nerve in the process. This condition is most common in athletes who perform repetitive extension movements and in older adults with degenerative spine conditions.

Pregnancy-Related Sciatica

During pregnancy, the growing uterus can place direct pressure on the sciatic nerve, particularly during the second and third trimesters. Hormonal changes that loosen the pelvic ligaments can also shift spinal alignment, contributing to nerve irritation. The reassuring news is that pregnancy-related sciatica typically resolves after delivery.

Key Risk Factors

Several factors increase the likelihood of developing sciatic nerve pain: age (disc degeneration progresses over time), obesity (excess weight increases spinal load), prolonged sitting or a sedentary lifestyle, diabetes (which can damage nerve tissue), and occupations that involve heavy lifting, twisting, or long hours of driving.

What Does Sciatic Nerve Pain Feel Like?

If you’ve ever wondered what does sciatic nerve pain feel like, the answer depends on where the nerve is being compressed and how severely. But most patients describe a very distinct set of sensations that set sciatica apart from ordinary back pain.

Classic Sensations

Sciatic pain is often described as a burning, shooting, or electric shock–like sensation that travels from the lower back through the buttock and down one leg. Some people experience a deep, stabbing ache. The pain is almost always one-sided and may extend through the thigh, calf, and into the foot. It can be constant or come in sudden waves.

Numbness, Tingling, and Weakness

Beyond pain, sciatica frequently causes pins-and-needles sensations in the leg or foot. You may notice muscle weakness when standing, walking, or climbing stairs. In more severe cases, a condition known as foot drop can develop, making it difficult to lift the front of the foot during normal walking.

When It Gets Worse

Sciatic symptoms tend to intensify with prolonged sitting or standing, which increases pressure on the disc. Coughing, sneezing, or straining can also worsen the pain. This is because these actions increase intra-abdominal pressure (known as the Valsalva effect), which is then transmitted to the spinal discs. Bending forward at the waist is typically the most aggravating movement.

How Sciatica Differs from Regular Back Pain

The key difference is simple: back pain stays in the back, while sciatica radiates down the leg. If your pain follows a path from the lower back through the buttock and into the leg, it’s far more likely to be sciatic nerve involvement than a muscle strain.

A useful self-check is the straight-leg raise: while lying flat on your back, slowly raise the affected leg. If this reproduces shooting pain down the leg, it’s a strong indicator of nerve compression. Of course, any persistent symptoms should be evaluated by a spine specialist for proper diagnosis.

Sciatica vs. General Back Pain: Back pain stays local. Sciatica travels. If your pain radiates from the lower back through the buttock and into the leg, nerve involvement is likely. See a spine specialist for evaluation.

How Long Does Sciatic Nerve Pain Last?

One of the most common questions patients ask is: how long does pain from the sciatic nerve last? Most cases of sciatic nerve pain last between 4 and 6 weeks and improve with conservative care. But the timeline can vary depending on the underlying cause and how quickly treatment begins.

Acute Sciatica (4–6 Weeks)

The majority of sciatica episodes resolve within this window. During the first week, pain may be most intense. By weeks two through four, many patients notice gradual improvement with gentle movement, over-the-counter anti-inflammatories, and targeted stretching. By week six, most people are functioning normally again.

Subacute Sciatica (6–12 Weeks)

When symptoms persist beyond six weeks, it typically signals a more significant underlying issue that warrants professional evaluation. This is the stage where physical therapy, chiropractic care, or a consultation with a spine specialist becomes particularly important.

Chronic Sciatica (12+ Weeks)

Sciatica lasting more than three months is considered chronic. At this stage, imaging studies such as an MRI are often recommended to identify the precise structural cause. Chronic sciatica can meaningfully impact daily life, sleep quality, and mental health, making early intervention all the more important.

Factors That Affect Recovery Time

Several factors influence how quickly sciatica resolves: your age, weight, and activity level all play a role. Starting treatment early versus waiting significantly changes outcomes. The specific underlying cause also matters. Disc herniations often respond faster to conservative care than spinal stenosis.

Can Sciatic Nerve Pain Cause Knee Pain?

Yes, the sciatic nerve can cause knee pain, and it’s more common than many people realize. The confusion arises because patients often assume knee pain must originate from the knee joint itself.

How Referred Pain Reaches the Knee

The nerve roots at the L3–L4 level supply sensation to the front and inner portions of the knee. The peroneal branch of the sciatic nerve also travels along the back of the knee and into the lower leg. When these nerve pathways are compressed higher up in the spine, the brain can interpret the signals as pain at the knee, a phenomenon known as referred pain.

Sciatica vs. Actual Knee Injury

Sciatica-related knee pain typically presents without swelling, without joint tenderness, and without a history of trauma. It’s often accompanied by back or buttock pain. In contrast, a true knee injury usually involves localized swelling, instability, and specific range-of-motion restrictions.

Getting a Proper Diagnosis

A straight-leg raise test and slump test can help identify whether the knee pain is related to nerve compression in the spine. If you’re experiencing persistent, unexplained knee pain, especially alongside back or leg symptoms. A consultation with a spine specialist can help determine whether the sciatic nerve is involved.

Can Sciatic Nerve Cause Hip Pain?

Absolutely. Hip pain caused by the sciatic nerve is a frequent finding in clinical practice, and it’s important to distinguish it from other common hip conditions so that treatment is directed at the right source.

The Hip-Spine Connection

The sciatic nerve passes directly through the gluteal region, in close proximity to the hip joint. Piriformis compression, in particular, can refer deep, aching pain into the hip and buttock that patients often mistake for a hip joint problem.

Sciatica vs. Hip Bursitis vs. Hip Arthritis

These three conditions produce distinctly different pain patterns. Sciatica causes pain that travels down the leg, often with tingling or numbness. Hip bursitis produces localized outer hip pain that worsens when lying on the affected side. Hip arthritis typically causes groin-area pain, stiffness after periods of rest, and reduced range of motion.

The FABER Test

The FABER test (Flexion, Abduction, External Rotation) is a simple physical assessment that helps distinguish hip joint pain from sciatic nerve pain. During the test, you lie on your back while the examiner positions your leg in a figure-four shape. Pain in the groin area suggests a hip joint issue, while pain in the back or buttock points toward a spinal or nerve origin. This is a screening tool. Always seek professional confirmation for a definitive diagnosis.

When to See a Doctor: Red Flag Symptoms

Most cases of sciatica improve with time and appropriate self-care. However, certain symptoms require immediate medical attention:

• Loss of bladder or bowel control. This may indicate cauda equina syndrome, a medical emergency that requires urgent surgical intervention.
• Progressive muscle weakness or foot drop that does not improve.
• Sciatica following a serious accident, fall, or direct injury.
• No meaningful improvement after 6 weeks of self-management.

If any of these apply to you, don’t wait. Early evaluation by a spine specialist can prevent permanent nerve damage and get you on the path to recovery.

Frequently Asked Questions Related to Sciatic Nerve Pain