Lumbar Radiculopathy: What Causes Sciatica and Nerve Root Pain in Your Lower Back?
Lumbosacral radiculopathy happens when a nerve root in the lower spine is pressed or irritated. This sends pain, tingling or weakness down your leg. It is the medical name for what most people call sciatica. A standing whole-body scan can show spinal alignment problems that add to nerve compression but do not show up when you are lying down.
Key points
- Lumbar radiculopathy is a pinched or irritated nerve root in the lower back. It is commonly called sciatica.
- Pain, numbness or weakness can travel from the buttock down the leg to the foot.
- Scans taken lying down can miss alignment shifts that press on nerve roots under your body weight.
- EOS standing imaging captures your full spine and pelvis in the position where symptoms actually occur.
- ScanAlign provides diagnostic imaging only. It does not treat the condition.
Your lower spine (the lumbar and sacral region) carries most of your body weight. Nerves branch out from the spinal cord between each vertebra. These form nerve roots that run down through your buttock and into your leg. When one of these roots is pinched, squeezed or irritated, the signals it carries are disturbed. The result is radiculopathy of the lumbosacral region, which most people simply know as sciatica.
The key point is this: the pain you feel in your leg often starts with a structural problem in your spine. And that problem can sometimes only be seen clearly when you are standing upright, carrying your own weight.
What are the symptoms of lumbar radiculopathy?
The main symptom is pain that travels from the lower back or buttock down one leg. It follows the path of the affected nerve. Which part of the leg hurts depends on which nerve root is involved.
A sharp or burning pain that runs from the buttock down the back, side or front of the leg, sometimes reaching the foot.
A "pins and needles" feeling in the leg, calf or foot, or patches of reduced feeling.
Difficulty lifting the foot (foot drop), weakness when pushing off, or a leg that gives way.
Symptoms often flare when upright, coughing, sneezing or bending, then ease when lying flat.
Urgent warning. If you develop sudden loss of bladder or bowel control, numbness around the groin or saddle area, or rapidly worsening weakness in both legs, seek medical help immediately. Contact your doctor, call your local emergency number, or go to the nearest emergency department. These symptoms may point to a serious condition that needs emergency care.
What causes sciatica and lumbar radiculopathy?
Lumbar radiculopathy occurs when something presses on a nerve root as it leaves the spine. Several structures can be responsible. Often more than one factor is involved.
The soft centre of a spinal disc pushes outward and presses on the nearby nerve root.
The bony canal around the spinal cord or nerve roots narrows, squeezing them.
One vertebra slips forward over the one below, narrowing the space for nerve roots.
Bony growths from wear and tear can press directly on the point where the nerve leaves the spine.
Your body is a connected chain from your feet to your head. If your pelvis tilts, your hip sits unevenly, or your lower back curve is too deep or too flat, the load on your lower spine changes. Over time, this uneven load can cause disc wear, joint thickening or a slipped vertebra in one area while another area compensates. This is why L4-L5 nerve root pain can be linked to an alignment problem much further along the chain.
How does a standing scan help diagnose lumbar radiculopathy?
A standing, weight-bearing scan shows your spine in the position where symptoms actually happen. When you lie down for a standard X-ray, CT or MRI, gravity is removed and muscles relax. Vertebrae can then shift back into a more normal position. So a narrowed nerve exit or a slipped vertebra can look less severe, or even disappear, on an image taken lying down.
EOS whole-body standing imaging captures your full skeleton, from head to feet, in a single upright scan. It uses about 90% less radiation than a standard X-ray, around ten times less. This gives your specialist a complete picture of how your lower spine, pelvis, hips and legs work together under real-life load.
Because the image shows your whole alignment, it can reveal whether a pelvic tilt, a difference in leg length, or a changed spinal curve is putting extra stress on the nerve roots at a specific level. A usual scan of the lower back alone would miss these wider mechanical factors.
Would you like to see how your full spinal alignment could be adding to your nerve pain?
Book a free video consultationA note on MRI. EOS excels at showing bony alignment, joint spacing and overall spinal balance in the standing position. For detailed views of soft tissue, such as discs, nerves and the spinal cord itself, MRI is usually the better tool. In many cases of lumbar radiculopathy, both types of imaging together give the most complete picture. Your clinician can advise which you need.
What generally helps with lumbar radiculopathy?
Most cases of sciatica improve within weeks to months. Care usually combines several approaches, guided by a healthcare professional.
- Staying active. Gentle movement is generally encouraged over long bed rest. Walking and light stretching can help you keep moving.
- Physiotherapy. Specific exercises can strengthen the muscles that support the spine and improve flexibility. Your physiotherapist can tailor these to your situation.
- Pain management. Your doctor or specialist may recommend suitable medication or other ways to relieve pain.
- Understanding the cause. Accurate imaging helps clinicians find the structural driver behind the nerve compression, so that any treatment targets the right level and the right problem.
ScanAlign provides the diagnostic imaging that informs these decisions. It does not offer treatment. Your scan results and clinical report are shared with the clinician you choose, so they can plan the best course of action for you.
Before you start treatment, or change the one you are on, it is worth getting a detailed diagnosis. Knowing whether the cause sits in your pelvis, your legs or your spine changes what will actually help.
Frequently asked questions about lumbar radiculopathy
They mean the same problem. Sciatica is the everyday word for pain along the sciatic nerve. Lumbar radiculopathy, or radiculopathy of the lumbosacral region, is the medical name. It means a nerve root in the lower spine is pressed or irritated, causing symptoms in the leg.
The L4, L5 and S1 nerve roots are the most often involved. Each one supplies different muscles and areas of feeling in the leg. The pattern of pain or weakness helps clinicians narrow down which level is affected.
Standard X-rays show bones, but not the nerves or discs directly. However, a standing EOS image can show narrowing of the disc space, a slipped vertebra, or alignment problems that set up the conditions for nerve compression. MRI is usually needed to see the nerve and disc detail directly.
When you lie down, gravity is removed. Muscles relax and vertebrae can shift back into a more normal position. A slipped vertebra or disc-space narrowing that presses on a nerve under your body weight may look less severe, or even normal, on a scan taken lying down. Standing imaging captures what is happening in real life.
Yes. EOS uses about 90% less radiation than a standard X-ray, around ten times less. You can find more details on our FAQs and safety page.
No. ScanAlign accepts self-referrals. You can book a free video consultation directly, without a letter from your doctor.
ScanAlign is a private, self-pay clinic. The price for patients travelling from abroad is confirmed during the free video consultation. You can find more on our FAQs page.
Yes. Your body works as a connected chain. A tilted pelvis, uneven leg lengths, or a changed hip position can shift the load on your lower spine. This increases pressure at a specific spinal level. Whole-body standing imaging shows these links, whereas a scan of the lower back alone would not.
Your images are reviewed and a detailed clinical report is written. This is shared with you and, if you wish, with your treating clinician. ScanAlign provides diagnostic imaging only and does not offer treatment.
Targeted exercises, guided by a physiotherapist, can help many people with lumbar radiculopathy by improving core support and flexibility. However, good rehabilitation depends on understanding the structural cause. Accurate imaging gives your physiotherapist the information they need to prescribe the right exercises for your situation.
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- NHS. Sciatica. nhs.uk/conditions/sciatica. Accessed 2024.
- National Institute for Health and Care Excellence (NICE). Low back pain and sciatica in over 16s: assessment and management (NG59). 2016, updated 2020.
- Deschênes S, et al. Diagnostic imaging of spinal deformities: reducing patients' radiation dose with a new slot-scanning X-ray imager. Spine. 2010;35(9):989-994.
Written by Abbas Dhami (Specialist Diagnostic Radiographer)
This page is general information and not a diagnosis.
ScanAlign is the trading name of CoreMed Solutions Ltd and operates under The Harley Street Hospital's CQC licence.