By Mr Ahmed-Ramadan Sadek, Neurosurgeon · Last reviewed October 2026 · 8 min read

What is sciatica?

The sciatic nerve is the largest nerve in the body. It is formed from several nerve roots that leave the lower spine (the lumbar and sacral spine) and join together in the buttock, before running down the back of the thigh and dividing into branches that supply the lower leg and foot.

When one of these nerve roots is pressed on or becomes inflamed, pain can travel along the path of the nerve. This is called sciatica. Doctors sometimes use the term lumbar radiculopathy, which simply means a problem with a nerve root in the lower back.

It is worth remembering that sciatica is a symptom rather than a diagnosis. It tells us that a nerve is irritated, but not why. Finding the cause helps guide the right treatment.

Symptoms

Sciatica feels different from person to person. Common symptoms include:

• Pain spreading from the buttock down the back or side of the leg, often below the knee and sometimes into the foot
• Leg pain that is often worse than any back pain
• A burning, shooting or electric-shock-like quality to the pain
• Pins and needles or numbness in the leg or foot
• Weakness in the leg or foot in some cases, such as difficulty standing on tiptoes or lifting the front of the foot
• Pain that may be worse when sitting, bending, coughing or sneezing

Symptoms usually affect one leg. The pattern of pain and numbness often gives a clue to which nerve root is involved. For example, the L5 nerve root tends to cause symptoms over the top of the foot and big toe, while the S1 nerve root tends to affect the sole and outer edge of the foot.

What causes sciatica?

• Slipped disc (disc prolapse): by far the most common cause, especially in people aged 30–50. Part of the soft centre of a disc pushes out and presses on a nerve root.
• Spinal stenosis: gradual narrowing of the spinal canal with age, from thickened ligaments, enlarged joints and bulging discs. This typically causes leg pain, heaviness or tingling when walking or standing, which eases on sitting or bending forward.
• Spondylolisthesis: one vertebra slipping forward on another, which can narrow the space for the nerves.
• Piriformis syndrome: a tight or irritated muscle deep in the buttock can cause very similar symptoms. The video at the top of this page explains how to tell them apart.
• Less common causes: rarely, infection, a fracture or a growth can press on a nerve. These are more likely if you also feel generally unwell, have a fever, unexplained weight loss, or a history of cancer.

How is sciatica diagnosed?

In most cases, sciatica is diagnosed from your description of the symptoms and an examination. Your doctor or physiotherapist may check your reflexes, muscle strength and sensation in your legs, and may ask you to lift your straight leg while lying down. This “straight leg raise” test often reproduces sciatic pain.

Scans are not always needed at first, because most sciatica improves on its own and early scans rarely change the treatment. An MRI scan is usually arranged if:

• symptoms are severe or not settling after around six weeks
• there is significant or worsening weakness
• there are warning signs of a more serious cause
• an injection or surgery is being considered

MRI shows the discs, nerves and soft tissues in detail without using radiation. It is important to know that disc bulges are very common on MRI, even in people with no pain at all, so scan findings always need to be matched to your symptoms.

Treatment options

Staying active and self-care

Keeping as active as you can, and gradually returning to your normal activities, generally helps recovery. Bed rest is no longer recommended, as it can lead to stiffness and slower recovery. Short walks, changing position regularly and gentle stretching can all help.

Simple pain relief, such as anti-inflammatory medicines if they are suitable for you, can help you keep moving. Your pharmacist or GP can advise on what is safe for you. Some medicines that used to be prescribed for sciatica are now used more cautiously, so it is worth reviewing your medication with your GP if it is not helping.

Physiotherapy

A physiotherapist can assess your movement and guide you through exercises to reduce pain, improve flexibility and build strength in your back, core and legs. Just as importantly, they can help you understand your symptoms and build confidence to stay active.

Nerve root injections

If leg pain is severe or slow to settle, an injection of local anaesthetic and steroid around the irritated nerve may help to calm it down. This does not fix the underlying cause, but it can reduce pain while the body heals. Read our guide to what to expect from a nerve root injection.

Surgery

Surgery is considered for a minority of patients. The most common operation is a microdiscectomy, in which the part of the disc pressing on the nerve is removed through a small incision. Surgery may be discussed when:

• severe leg pain continues despite several weeks of non-surgical treatment
• there is significant or worsening weakness
• there are signs of cauda equina syndrome, which is an emergency

Surgery is generally very effective at relieving leg pain, but is less predictable for back pain. Your surgeon will talk you through the benefits and risks so you can make an informed decision together. Read more in our slipped disc guide.

Outlook

The outlook for sciatica is good. Most people recover well, usually within weeks to a few months. Symptoms can come back, and staying active, keeping a healthy weight and maintaining strength in your core and leg muscles may help reduce this risk.

If your pain is not improving, is getting worse, or is stopping you from working or sleeping, speak to your GP. Sometimes a referral to a spinal specialist is the right next step.

This guide is general information and is not a substitute for advice about your own situation. Please speak to your GP or specialist.