Femoral Nerve Injury – When Walking Becomes a Challenge

Sudden weakness in the leg, difficulty climbing stairs, or numbness at the front of the thigh? These symptoms may be caused by a femoral nerve injury – a problem affecting an important nerve running through the groin and supplying the front of the thigh. If the femoral nerve is impaired, it can lead to significant thigh weakness, making walking, standing, and getting up from a chair much more difficult.

What does the femoral nerve do?

The femoral nerve begins in the lower back at the lumbar spine. From there, it travels through the pelvis into the groin and then down the front of the thigh.

It has two main functions:

Movement: controls knee extension and helps lift the leg.
Sensation: carries feeling from the skin at the front of the thigh and the inner side of the lower leg.

Anatomical illustration of the groin region showing the femoral nerve (yellow), femoral artery (red), and femoral vein (blue). — Anatomical view of the groin region with the femoral nerve, femoral artery, and femoral vein.

Without the femoral nerve, stable walking, standing, and rising from a seated position would hardly be possible.

Typical symptoms

A femoral nerve injury can cause a variety of signs and symptoms. People often report:

Weakness when climbing stairs or standing up from a chair
The feeling that the knee might give way
Pain, burning, or pulling sensations in the groin or at the front of the thigh
Numbness or tingling at the front of the thigh, sometimes extending to the inner side of the lower leg
In severe cases, inability to actively straighten the knee – a clear sign of thigh weakness

Illustration showing a man with femoral nerve injury complaining of leg weakness when climbing stairs. — A feeling of weakness when climbing stairs or rising from a chair can be a sign of femoral nerve damage.

Possible causes

The femoral nerve can be affected at various points along its path from the spine to the thigh. Most often, this happens through compression, stretching, or injury in the lumbar spine, pelvis, or groin. Common causes include:

Surgery in the pelvis or groin area, such as hernia repair, hip surgery, or vascular procedures
Bruising or haematomas, for example after injury or in cases of increased bleeding tendency
Space-occupying lesions such as tumours or enlarged lymph nodes
Diabetes, rarely causing an isolated nerve injury
Accidents or direct trauma to the nerve

Other possible causes of similar symptoms (differential diagnoses)

Not all thigh weakness or numbness is due to a femoral nerve injury. Other conditions can mimic these symptoms:

Lumbar disc herniation: can compress nerve roots and cause pain or weakness in the front of the thigh
Diabetic amyotrophy: a rare nerve inflammation in diabetes with sudden, severe thigh pain and weakness
Hip disorders such as osteoarthritis: often cause groin pain without direct nerve damage
Circulatory problems: can lead to weakness or pain in the leg
Meralgia paraesthetica: irritation of a skin nerve on the outer thigh causing burning or tingling, but no muscle weakness

How is the diagnosis made?

1. Clinical examination

Testing strength, reflexes, and sensation in the affected leg
Specific movement tests can help distinguish whether the problem lies in the femoral nerve, the nerve roots, or other structures

2. MRI (Magnetic Resonance Imaging)

Lumbar spine MRI: checks for disc herniation or narrowing of the nerve root canals
Pelvic MRI: shows deeper nerve segments and structures, useful when looking for bruising or space-occupying lesions
Particularly suited for areas not well visualised by ultrasound

3. High-resolution nerve and muscle ultrasound

Directly visualises the femoral nerve from the groin onwards
Detects changes such as swelling, scarring, or bleeding
Can be performed dynamically (during movement)
No radiation exposure and suitable for repeated follow-up
Muscle ultrasound can also be performed to assess changes in muscles supplied by the femoral nerve, such as shrinkage or texture changes

4. Neurophysiological tests

Electromyography (EMG): measures the electrical activity of muscles. Selecting specific muscle areas can help pinpoint the site of nerve involvement more accurately. Muscle ultrasound can guide EMG to the most affected areas, reducing the number of needle insertions needed.
Nerve conduction studies: measure how quickly electrical signals travel along the nerve

Why nerve ultrasound is particularly helpful

High-resolution nerve ultrasound offers key advantages in suspected femoral nerve injury. It allows direct visualisation of the nerve in the groin and can detect swelling, narrowing, scar tissue, or bleeding.

Unlike MRI or X-ray, ultrasound can assess the nerve in motion – for example, during changes in position – which can reveal positional compression.

It also enables examination of the surrounding muscles, helping detect early changes caused by nerve dysfunction.

Because it is radiation-free, painless, and repeatable, nerve ultrasound is suitable for both initial diagnosis and follow-up.

Treatment – depending on the cause

Treatment of a femoral nerve injury depends primarily on the underlying cause and the extent of nerve damage. Which measures are appropriate should always be decided individually after specialist medical evaluation.

Possible measures include:

Relieving pressure on the nerve, for example by addressing bruises or space-occupying lesions
Physiotherapy to strengthen the thigh muscles, improve mobility, and stabilise posture
Pain management using medication or physical therapy
Treating underlying conditions, such as optimising blood sugar control in diabetes or adjusting blood-thinning medication under medical supervision
Surgery in selected cases where a clear mechanical cause is present that cannot be resolved otherwise

Schematic illustration of a personalized treatment plan with a central symbol surrounded by medical options. — Every treatment plan should be tailored to the symptoms and needs of the individual.

Summary

A femoral nerve injury can make walking, climbing stairs, and getting up from a chair significantly harder. Because similar symptoms can arise from other conditions, a careful assessment is essential.

A combination of clinical examination, MRI, nerve and muscle ultrasound, and neurophysiological testing such as EMG usually provides the information needed to identify the cause.

Targeted, specialist-guided treatment can then help to relieve pressure on the nerve, maintain mobility, and prevent further complications.

Disclaimer: The information provided on this page is for general informational purposes only and does not constitute medical advice. It is not a substitute for personal consultation, examination, or treatment by a physician or other qualified healthcare professional. No guarantees of healing or cure are made. While we strive for accuracy and completeness, we cannot guarantee that all content is up to date or free from errors, and we accept no liability for any inaccuracies.