22 Mar, 2023

MRI for Sciatica: Symptoms, Causes, Diagnosis, and Treatment Options

Introduction to the sciatic nerve

Sciatica is a condition that affects the sciatic nerve, which is the largest nerve in the human body. The sciatic nerve runs from the lower back through the hips and buttocks and down the legs. Sciatica can cause pain, numbness, and tingling sensations in the affected leg. In this blog post, we will discuss the symptoms, causes, diagnosis, and treatment options for sciatica.

Symptoms of sciatica

The most common symptom of sciatica is radiating pain from the lower back down one leg. The pain can range from mild to severe and can feel like a sharp, shooting pain or a dull ache. Other symptoms of sciatica include:

  • Numbness or tingling sensations in the leg

  • Weakness in the affected leg

  • Pain that worsens when sitting or standing for long periods

  • Pain that improves when lying down

  • Pain that radiates down the leg to the foot

  • Muscle spasms in the affected leg

  • Changes in your bowel and bladder control

Causes of sciatica

Sciatica is usually caused by a herniated disk or a bone spur that puts pressure on the sciatic nerve. Other causes of sciatica include spinal stenosis (narrowing of the spinal canal), degenerative disc disease (wear and tear of the spinal discs), and spondylolisthesis (when one vertebra slips out of place onto another vertebra).

Diagnosis of sciatica: How do doctors test for sciatica?

If you experience any of the above symptoms, you should seek medical attention. Your healthcare provider will perform a physical exam to check for muscle weakness, sensory deficits, and reflex changes. They will also take a detailed medical history to determine if you have any underlying medical conditions that may be contributing to your symptoms. Imaging tests such as magnetic resonance imaging (MRI), or computerised tomography (CT) scans may be recommended to confirm the diagnosis of sciatica.

Why might an MRI scan be recommended for Sciatica?

Imaging tests for sciatica are only really recommended if your symptoms do not improve after 6-8 weeks, or if you have chronic sciatica pain.

An MRI scan is a non-invasive imaging test that uses magnetic fields and radio waves to create detailed images of the body's internal structures and soft tissues. It can provide a clear picture of the spine, nerves, and surrounding tissues, which can help doctors identify any abnormalities that may be causing the symptoms of sciatica. These include:

  • Herniated disc: An MRI scan can show whether a disc in the spine has herniated or ruptured, which can cause pressure on the sciatic nerve.

  • Spinal stenosis: This condition occurs when the spinal canal narrows, putting pressure on the nerves in the spinal cord. An MRI scan can show whether there is any narrowing of the spinal canal.

  • Degenerative disc disease: An MRI scan can show whether there is any damage to the discs in the spine, which can cause them to break down and put pressure on the nerves.

An MRI scan can also help doctors rule out other conditions that may be causing the symptoms of sciatica, such as tumours or infections, or it can help identify whether you would be suitable for epidural steroid injections to reduce pain.

What type of MRI is recommended for Sciatica pain?

To identify the cause of sciatica symptoms, an MRI scan of the lumbar spine is usually recommended - even though sciatica can manifest as leg pain. This is because the sciatic nerve root is located in the lower back.

This area of the spine is located in the lower back and is the most common site of sciatica, as most sciatica cases are caused by herniated discs pressing on the nerve. An MRI scan of the lumbar spine can provide detailed images of the spinal cord, nerves, and surrounding tissues in this area, to check what might be causing ongoing symptoms.

In some cases, an MRI scan of the pelvis may also be recommended to help identify any abnormalities in the pelvic region that may be causing the symptoms of sciatica.

Can you diagnose sciatica without an MRI?

It is possible to get your sciatica diagnosed with a physical examination and complete medical history, which does not require imaging such as MRI. However, if your pain persists even after conservative treatments, lasts longer than 3 months or continuously reoccurs (chronic sciatica), or leads to severe weakness, your doctor may recommend an MRI to rule out any other pathology and support your treatment and onward care.

Treating sciatica: what can be done?

Self care treatments and alternative therapies

Most patients with sciatica recover with conservative treatment to treat sciatica pain. Self-care measures such as bed rest, hot packs or cold packs, and proper posture can help relieve sciatica pain. Over-the-counter painkillers such as ibuprofen can also offer pain relief.

Alternative therapies such as acupuncture, acupressure and yoga can help relieve sciatica pain for some patients, but should be carried out with guidance from your healthcare professional.

Physical therapy

Physical therapy can also be an effective nonsurgical treatment for sciatica. Physical therapists can teach you exercises that can help relieve pain and prevent future flare-ups. Massage therapy, spinal manipulation, and physiotherapy can also be beneficial in relieving sciatic pain.

Medical interventions and surgeries

If self-care measures and physical therapy do not relieve your sciatica pain, your healthcare provider may recommend other treatments such as epidural steroid injections. Nonsurgical treatment is usually all that is necessary, but in rare cases, surgery may be necessary to relieve the pressure on the sciatic nerve.

Prevention of Sciatica

There are numerous risk factors that can increase the likelihood of experiencing sciatica, and by addressing these risks, sciatica can be prevented.

The best way to prevent sciatica is to maintain a healthy weight, exercise regularly, and practice good posture. Avoid sitting or standing for long periods, and take frequent breaks to stretch and walk around. This can prevent disc herniation and strengthen the muscles supporting the spinal column.

If you experience sciatica, seek immediate medical attention to prevent permanent nerve damage.


Sciatica can cause severe pain and discomfort, but most patients recover with conservative treatment and self-care measures. If you experience any symptoms of chronic sciatica such as the pain going on for more than a few weeks or even months, you might be recommended an MRI scan.

Sometimes, sciatica pain could be a sign of something more sinister, and an MRI scan can help rule out or diagnose those issues, to help you access the best possible treatment. Research in the British Journal of Radiology showed that early diagnosis of sciatica is key to improving the likelihood of pain relief, while avoiding further injury or surgery that could have been prevented.

That's why, if you are suffering with sciatica, you should visit your healthcare professional for an examination, treatment suggestions, and onward monitoring.

Next steps:

  • Book your lumbar spine MRI to find out what is causing your sciatica pain, and get advice from our clinicians, with a pre-consultation included in the price.

  • Find out more about lumbar spine MRI in our body areas directory.

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