Slump test: how to perform and interpret it

The slump test assesses sensitivity of the lower-limb nervous system, often in suspected lumbar radiculopathy. The seated patient slumps, flexes the neck, then extends the knee and dorsiflexes the ankle. It is positive when it reproduces the patient's symptoms and those symptoms change when the neck is released.

Purpose

To tension the neuraxis and sciatic nerve tract and check whether symptoms are neural in origin.

How to perform the Slump test

  • Seat the patient with thighs supported and hands behind the back.
  • Ask them to slump through the thoracic and lumbar spine while you hold the position.
  • Add neck flexion.
  • Extend the knee on the symptomatic side, then dorsiflex the ankle.
  • Release neck flexion and note whether symptoms change (structural differentiation).
  • Repeat on the other side for comparison.

Positive result and interpretation

Reproduction of the patient's familiar symptoms that change with a distant movement, such as releasing neck flexion.

Supports neural mechanosensitivity, for example from lumbar nerve root involvement. Posterior thigh stretch that does not change with neck movement is a normal response.

Cluster it with

  • Straight leg raise
  • Neurological examination (myotomes, dermatomes, reflexes)
  • History of dermatomal leg pain worse than back pain

Common mistakes

  • Skipping structural differentiation - hamstring stretch alone is not a positive result.
  • Not comparing with the other side.
  • Performing it before screening for cauda equina signs.

Frequently asked questions

What is the difference between the slump test and straight leg raise?

Both tension the sciatic nerve tract. The slump test is performed seated and adds spinal and neck flexion, making it more sensitive; the straight leg raise is supine and easier to perform in irritable patients.

Is a positive slump test always a disc herniation?

No. It shows the nervous system is sensitive to movement, which can occur with disc herniation, stenosis, or other causes of neural irritation. Interpret it with the history and neurological examination.