What Causes Foot Drop, and How Urgent Is It?
Foot drop is difficulty lifting the front of your foot. It is usually caused by pressure on the common peroneal nerve at the knee, or by nerve root compression in the lower back, most often at the L5 level. New or worsening foot drop needs prompt medical assessment because early diagnosis improves recovery.
Key takeaways
- Foot drop means you cannot lift your toes and forefoot properly when walking.
- The most common causes are peroneal nerve injury at the knee or a compressed nerve root in the lower back.
- New foot drop with numbness, weakness, or bladder or bowel changes is a medical emergency.
- Standing whole-body imaging can reveal spinal alignment problems that lying-down scans may miss.
- Early assessment gives you the best chance of recovery.
How urgent is foot drop?
It depends on how quickly it appeared and whether other symptoms are present. A foot drop that comes on suddenly, especially alongside back pain, leg weakness, or changes in bladder or bowel control, may indicate a serious spinal problem such as cauda equina syndrome. This needs emergency care.
Seek urgent medical attention (GP, 111, or A&E) if you have new foot drop together with any of the following:
- Numbness around the groin or inner thighs (saddle area)
- Loss of bladder or bowel control
- Rapidly worsening leg weakness
- Sudden severe back pain
Do not wait for a private scan. These symptoms require immediate assessment.
If your foot drop has developed gradually and you have no red-flag symptoms, it still deserves proper investigation. The longer a nerve is compressed, the harder recovery becomes. Speak to your GP or a specialist promptly.
How do you know if you have foot drop?
You may notice that you cannot lift the front of your foot properly, causing your toes to drag or catch on the ground when you walk. Many people change the way they walk without realising it.
Your toes catch on kerbs, steps, or uneven ground more than they used to.
You lift your knee higher than normal to stop your foot dragging. This is sometimes called a steppage gait.
Your foot slaps down on the floor when you step because you cannot control the landing.
Reduced sensation over the top of the foot or outer shin, suggesting nerve involvement.
What causes foot drop?
Foot drop is a symptom, not a condition in itself. It happens when the nerve signal that tells your foot to lift is interrupted somewhere along its path, from the lower back down to the knee. The two most common sites of trouble are the common peroneal nerve at the outside of the knee and the L5 nerve root in the lumbar spine.
The nerve wraps around the head of the fibula, just below the knee, where it is vulnerable to pressure from tight casts, leg crossing, or direct injury.
A bulging or herniated disc in the lower back can compress the L5 nerve root, causing L5 radiculopathy with weakness in the muscles that lift the foot.
Narrowing of the spinal canal can gradually squeeze nerve roots. This is more common with age and can cause lumbar radiculopathy.
Less common causes include stroke, motor neurone disease, diabetes-related nerve damage, and hip or knee surgery complications.
Because the nerve travels a long path from the spine to the foot, the cause of foot drop is not always at the site of the symptoms. A problem in your lower back can produce weakness at your ankle. This is why a full assessment matters.
How does standing imaging help with foot drop?
Standing imaging shows your spine and lower limbs under the same load they carry all day. When you lie down for a standard X-ray, CT or MRI, your muscles relax and gravity is removed. Alignment problems that only show up when you are weight-bearing can be hidden.
Your body works as a connected chain from your feet to your head. If your pelvis tilts or your spine shifts to one side, the nerve roots in your lower back can come under pressure that a lying-down image would not show. ScanAlign standing EOS imaging captures a full-length image of your skeleton while you stand naturally, using about 90% less radiation than a standard X-ray, around ten times less.
For someone with foot drop that has not been fully explained by other tests, a standing whole-body assessment can reveal spinal or pelvic alignment shifts that may be contributing to the nerve compression.
When MRI is the better tool: EOS imaging shows bones, joints and alignment. For soft tissue detail, such as a herniated disc pressing on a nerve, MRI is usually the better investigation. In many cases, both standing alignment imaging and MRI together give the fullest picture.
If your foot drop has been investigated but the cause remains unclear, a standing whole-body assessment may reveal alignment factors other imaging missed.
Book a free video consultationWhat should you do if you think you have foot drop?
The right first step depends on how quickly your symptoms appeared.
- See your GP urgently or attend A&E
- Mention any back pain, numbness, or bladder changes
- You may need emergency MRI and specialist review
- You may have had MRI, nerve conduction studies, or physiotherapy already
- Standing alignment imaging can check whether spinal or pelvic alignment is contributing
- A free video consultation can help you decide if this is the right next step
Recovery from foot drop varies. It depends on the cause, how long the nerve has been compressed, and how quickly treatment begins. Some people recover fully, while others need ongoing support such as an ankle-foot orthosis to help with walking. ScanAlign does not provide treatment. It provides the diagnostic imaging that helps your treating clinician plan the right approach.
If your symptoms include nerve root compression in the lower back, understanding your whole-body alignment can be an important part of the diagnostic picture. You can book an assessment to discuss your situation with a specialist radiographer first.
Frequently asked questions about foot drop
It can, especially if the cause is temporary pressure on the peroneal nerve, such as from a cast or habitual leg crossing. If a compressed nerve root in the spine is responsible, recovery depends on relieving that pressure. The sooner the cause is identified, the better the outlook.
It can be. While many cases are caused by treatable nerve compression, foot drop can occasionally be a sign of stroke, motor neurone disease, or cauda equina syndrome. New foot drop always warrants medical review.
The peroneal nerve can be compressed at the knee, causing weakness localised to the foot and outer shin. An L5 nerve root problem originates in the lower back and can cause broader symptoms including back pain, hip weakness, and numbness down the leg as well as foot drop.
No. ScanAlign accepts self-referrals. You start with a free video consultation where a specialist radiographer reviews your situation before any scan is booked.
An EOS scan uses about 90% less radiation than a standard X-ray, around ten times less. This makes it especially suitable when full-body images are needed.
When you lie down, gravity is removed and your muscles relax. Spinal alignment shifts that happen under normal standing load, such as a pelvic tilt or lateral lean, may flatten out. If these shifts are contributing to nerve compression, a lying-down scan may not show them.
EOS imaging shows bone and joint alignment under load. It can reveal spinal or pelvic alignment problems that contribute to nerve compression. However, to see soft tissue such as a herniated disc, MRI is usually needed as well. The two investigations complement each other.
ScanAlign is a private, self-pay clinic. Pricing details are available on the FAQs and cost page. The initial video consultation is free.
Common investigations include MRI of the lumbar spine, nerve conduction studies (which test electrical signals in the nerve), and standard X-rays. Standing whole-body imaging adds alignment information that other tests do not capture.
A specialist radiographer will listen to your history, review any previous imaging you may have, and explain whether a standing alignment assessment is likely to add useful information in your case. There is no obligation to proceed.
Still have questions about foot drop?
A free video consultation with a specialist radiographer can help you understand whether standing alignment imaging is the right next step.
Book a free video consultationWritten by Abbas Dhami (Specialist Diagnostic Radiographer)
Sources
- NHS. "Foot drop." nhs.uk. Accessed 2024.
- Stewart JD. "Foot drop: where, why and what to do?" Practical Neurology. 2008;8(3):158-169.
- American Academy of Orthopaedic Surgeons. "Foot Drop." OrthoInfo. Accessed 2024.
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.