Back pain is common enough that most people learn to live with it. But when that pain starts running down one leg, past the knee, sometimes all the way to the foot, it stops being an ordinary ache and starts raising a specific question: is this sciatica? The distinction matters, because sciatica points to a specific mechanical cause with a fairly predictable treatment path, while other causes of leg pain need to be ruled out or managed differently entirely.

Quick answer: Sciatica is nerve pain caused by irritation or compression of the sciatic nerve roots, usually from a herniated disc in the lower back. The hallmark sign, according to a bone specialist in Delhi, is pain radiating from the lower back or buttock down the back of one leg, often below the knee, frequently with tingling, numbness, or weakness along the same path.

What Exactly Is Sciatica?

Sciatica is not a diagnosis in itself; it’s a symptom pattern caused by irritation of the sciatic nerve roots, which originate in the lower spine (typically L4 through S1) and run down through the buttock and the back of the leg to the foot. When one of these nerve roots is compressed or inflamed, pain, tingling, numbness, or weakness can travel anywhere along that path, which is why sciatica pain is often felt well below where the actual problem sits in the spine.

Referred low back pain, by contrast, tends to stay localised to the back and buttock without extending clearly below the knee, and doesn’t typically follow the sharp, shooting, electric quality that characterises true nerve root pain.

Sciatica vs. Other Causes of Radiating Leg Pain

Not all leg pain that starts in the back is sciatica. The table below outlines how sciatica differs from two commonly confused conditions.

Feature	True Sciatica	Piriformis Syndrome	Vascular Claudication
Pain trigger	Sitting, bending, coughing	Sitting or hip rotation specifically	Walking a consistent distance
Pain relief	Lying down or changing position	Stretching the piriformis muscle	Stopping to rest; relief is rapid
Associated signs	Numbness, tingling, weakness along the nerve path	Deep buttock pain, rarely past the knee	Leg cramping, cold sensation, not true numbness
Underlying cause	Disc or spinal nerve root compression	Muscle compressing the nerve, no disc involvement	Reduced blood flow in the leg arteries

What Actually Causes Sciatica?

A herniated or bulging disc pressing on a nerve root is the single most common cause, accounting for the large majority of cases seen in clinical practice. Lumbar spinal stenosis, a narrowing of the spinal canal that tends to develop with age, is another frequent cause, often producing pain that worsens with walking and eases with sitting or bending forward. Spondylolisthesis, where one vertebra slips forward over the one below it, and piriformis syndrome, where a deep buttock muscle irritates the nerve without any disc involvement at all, round out the more common mechanical causes.

How Doctors Actually Test for Sciatica

The straight leg raise (SLR) test remains the most widely used bedside test: with you lying flat, the examiner lifts your straight leg, and pain reproduced between roughly 30 and 70 degrees of elevation, particularly if it shoots below the knee, suggests nerve root involvement rather than simple muscular tightness.

A more specific variation, the crossed straight leg raise, lifts the unaffected leg instead. If this reproduces pain in the affected leg, it’s a notably reliable sign, research places its specificity at around 88 to 90% for nerve root compression, meaning a positive result is a strong indicator, even though it doesn’t occur in every genuine case.

The slump test, performed seated with the neck and trunk flexed forward while extending the knee, is often used alongside the SLR to build a fuller clinical picture. None of these tests replace imaging when the diagnosis is unclear or red flags are present, but together they let an orthopaedic specialist form a confident clinical impression before ordering an MRI.

Imaging: When Is an MRI Actually Needed?

Most sciatica doesn’t need imaging right away. Guidelines generally reserve MRI for cases with red flag symptoms, significant or progressive weakness, or pain that hasn’t responded to four to six weeks of proper conservative treatment, since imaging findings like mild disc bulges are also common in people with no pain at all, and an early scan can sometimes lead to treatment that isn’t actually necessary. When imaging is warranted, MRI is preferred over X-ray, since X-rays show bone well but don’t visualise the disc or nerve tissue that’s actually causing sciatic pain.

Red Flags: When Radiating Leg Pain Is a Medical Emergency

The overwhelming majority of sciatica is mechanical and not dangerous, but a small subset of cases signal a genuine emergency called cauda equina syndrome, compression of the nerve bundle at the very base of the spinal cord. Seek immediate emergency care, not a routine appointment, if you experience any of the following alongside back or leg pain:

• Numbness in the “saddle” area, the inner thighs, buttocks, and groin, the area that would touch a saddle
• New difficulty starting urination, a feeling of incomplete bladder emptying, or loss of bladder control
• New loss of bowel control
• Progressive weakness affecting both legs, rather than just one

This combination is rare, but when it occurs, the window for surgical decompression to prevent permanent nerve damage is measured in hours, not days, which is precisely why these specific symptoms override the usual “wait and see” approach to back pain.

How Is Sciatica Actually Treated?

Most sciatica, even when genuinely painful, improves with conservative management over four to six weeks. This typically includes staying reasonably active rather than prolonged bed rest, anti-inflammatory medication, and targeted physiotherapy focused on nerve mobility and core stability. Heat or cold application can ease acute discomfort, though neither addresses the underlying nerve irritation directly.

If pain persists significantly beyond six weeks despite proper conservative treatment, an epidural steroid injection is often considered next, delivering anti-inflammatory medication directly around the irritated nerve root to reduce swelling and allow the underlying issue time to settle.

When Does Sciatica Actually Need Surgery?

Surgery is generally reserved for cases with confirmed nerve root compression on imaging that hasn’t responded to several weeks of appropriate conservative care, or for cases involving significant, progressive muscle weakness, not just pain. Microdiscectomy, removing the specific portion of disc material pressing on the nerve, is the most common surgical approach and typically allows a relatively quick return to normal activity. Cauda equina syndrome is the one clear exception to a “try conservative treatment first” approach; this requires urgent surgical decompression, not a trial of physiotherapy.

Preventing Sciatica From Recurring

Once an episode resolves, core and lower back strengthening genuinely reduces the odds of recurrence, since a stronger surrounding musculature takes pressure off the discs and nerve roots during daily movement. Maintaining a healthy body weight reduces the mechanical load on the lower spine, and paying attention to lifting technique, bending at the knees rather than the waist, protects the discs during everyday tasks. Prolonged sitting without breaks is a genuine contributing factor for many people, worth addressing directly if your sciatica is linked to a desk-based routine.

When to See an Orthopaedic Specialist in Dwarka

Book a consultation with an orthopaedic specialist in Dwarka if leg pain persists beyond one to two weeks, is severe enough to limit walking or daily activity, or comes with numbness or weakness that isn’t improving. Seek emergency care immediately, rather than booking a routine appointment, for any of the red flag symptoms described above.

Not every ache running down your leg is sciatica, and not every case of genuine sciatica needs surgery, but knowing the difference, and recognising the handful of symptoms that turn this into a genuine emergency, changes how you should respond. If your back pain has started travelling down your leg and hasn’t meaningfully improved within a week or two, an orthopaedic evaluation gives you a real answer rather than a guess. The Bone Clinic in Dwarka offers experienced orthopaedic assessment to help you find out exactly what’s going on and the most effective way to treat it.

Frequently Asked Questions

How long does sciatica usually take to heal?

Most cases improve significantly within four to six weeks with appropriate conservative treatment, though some people notice gradual improvement continuing for a few months, particularly if nerve irritation was more severe.

Can sciatica happen on both legs at the same time?

It’s uncommon for true sciatica, which typically affects one side. Pain or weakness affecting both legs at once is actually one of the red flag patterns worth getting evaluated promptly rather than assumed to be a more severe version of ordinary sciatica.

Is walking good or bad for sciatica?

For most mechanical sciatica, gentle walking is generally encouraged rather than avoided, since prolonged inactivity can slow recovery. That said, if walking consistently worsens your specific pain, this is worth discussing with your doctor rather than pushing through it.

Does sciatica show up on a standard X-ray?

No. X-rays show bone alignment well but don’t visualise discs or nerves, which is why MRI, not X-ray, is the imaging test actually used to confirm the cause of genuine sciatica when imaging is needed.

Can sitting all day at a desk actually cause sciatica?

Prolonged sitting doesn’t directly herniate a disc on its own, but it does increase pressure on the lower spine and is a recognised contributing factor, particularly combined with poor posture or weak core muscles, which is why regular breaks and posture matter for prevention.