What tests check for nerve compression in the leg? 

When a person in the United Kingdom experiences shooting pain, numbness, or weakness in their leg, a healthcare professional must determine if these symptoms are caused by nerve compression. In the majority of cases, this is done through a physical examination known as a neurological assessment. By performing a series of specific movements and sensory checks, a GP or physiotherapist can identify which nerve is being affected and where the compression is likely occurring, often in the lower spine. These tests are highly reliable and usually eliminate the need for immediate imaging like an MRI. 

What We’ll Discuss in This Article 

• The Straight Leg Raise (SLR) and other tension tests 

• Neurological checks for sensation, strength, and reflexes 

• Understanding dermatomes and myotomes 

• The Slump Test for spinal nerve irritability 

• Identifying “Red Flag” symptoms during testing 

• NHS and NICE standards for clinical nerve assessments 

Neural Tension Tests: The Straight Leg Raise 

The most common and evidence-based test for checking nerve compression in the leg is the Passive Straight Leg Raise (SLR). This test is specifically designed to check for irritation of the sciatic nerve, which is often caused by a slipped disc in the lower back. 

1. The Procedure: You lie flat on your back, and the clinician slowly lifts your affected leg while keeping the knee straight. 

2. The Response: If the movement reproduces your familiar shooting leg pain at an angle between 30 and 70 degrees, the test is considered positive for nerve root irritation. 

3. The Bragard Sign: If the clinician then lowers the leg slightly and pulls your toes toward your shin (dorsiflexion), it increases the stretch on the nerve. If this brings the pain back, it further confirms nerve involvement. 

The Slump Test 

For patients who can comfortably sit, a clinician may use the Slump Test. This is another way to put the spinal cord and the leg nerves under tension to see if they are sensitive. 

• You sit on the edge of the couch and “slump” your shoulders forward. 

• You tuck your chin to your chest and slowly straighten your knee. 

• Finally, you pull your toes toward you. According to NICE clinical standards, if these combined movements trigger your leg symptoms, it is a strong indicator of neural sensitivity or compression in the lumbar spine. 

Neurological Assessment: Reflected Function 

Nerve compression is not just about pain; it is about how well the nerve is “communicating” with the rest of your body. A clinician will check three specific areas of nerve function: 

1. Sensory Testing (Dermatomes) 

Each nerve root in your back provides feeling to a specific patch of skin on your leg, known as a dermatome. The clinician may use a light touch or a pinprick to see if you have patches of numbness or “pins and needles.” 

• L4: Typically provides sensation to the inner calf. 

• L5: Provides sensation to the top of the foot and the big toe. 

• S1: Provides sensation to the outer edge of the foot and the little toe. 

2. Strength Testing (Myotomes) 

Nerves also tell your muscles when to contract. By testing the strength of specific movements, a clinician can tell which nerve root might be compressed. 

• Knee Extension (L3/L4): Pushing your leg out straight. 

• Big Toe Lift (L5): Pulling your big toe toward your shin. 

• Ankle Push (S1): Pushing your foot down as if pressing a car pedal. 

3. Reflex Testing 

A diminished or absent reflex is a classic sign of nerve compression. The clinician will use a reflex hammer to tap the tendon below your kneecap (L3/L4) and the Achilles tendon at the back of your ankle (S1). A normal “kick” suggests the nerve pathway is clear, while a weak response suggests the signal is being interrupted. 

The Femoral Nerve Stretch Test 

While sciatica is the most common form of leg nerve compression, the femoral nerve (located at the front of the thigh) can also be affected. To test this, you lie on your front and the clinician bends your knee toward your bottom while lifting your thigh off the bed. If this causes sharp pain or tingling in the front of your thigh, it suggests compression of the L2, L3, or L4 nerve roots. 

Conclusion 

Physical tests like the straight leg raise, combined with checks for strength, sensation, and reflexes, provide a comprehensive picture of nerve health in the leg. In the UK, these clinical tests are the primary way GPs and physiotherapists diagnose nerve compression. Most symptoms improve within 4 to 6 weeks with gentle movement and appropriate management. If you experience severe, sudden, or worsening symptoms, or if you lose control of your bladder or bowels, call 999 immediately. 

Authority Snapshot (E-E-A-T Block) 

This article describes the evidence-based physical tests used by UK healthcare professionals to assess leg nerve compression. The content is written by the MyPatientAdvice Medical Writing/Research Team and reviewed by Dr. Rebecca Fernandez to ensure alignment with the latest NHS and NICE clinical protocols. Our purpose is to provide clear, accurate medical education for patients.