Clinical Tests for Lumbar Segmental Instability

Last Updated on May 11, 2025

Lumbar segmental instability may not always be visible on standard imaging, especially in the early or functional stages. In such cases, a series of physical examination tests can help identify abnormal motion, muscle coordination deficits, or segmental pain provocation that suggests instability. [1]

These clinical tests are particularly useful in [2]

• Patients with chronic mechanical low back pain
• Suspected cases of functional (non-structural) instability
• Situations where radiographs are inconclusive

While none of these tests are diagnostic in isolation, they provide valuable insight when interpreted in context along with imaging and history.

For a complete overview of lumbar segmental instability, including causes, imaging, and treatment, read the main article- Lumbar Segmental Instability

Gower’s Sign

Gower’s Sign is a clinical observation made during a patient’s attempt to return to an upright position from trunk flexion. The patient places their hands on the thighs and uses them to “climb up” the legs for support. [3]

Method:

• Ask the patient to bend forward at the waist and then return to standing.
• Observe for the use of hands or arms to push against the thighs or knees.

Interpretation

This maneuver suggests lumbar extensor muscle weakness, poor trunk control, or segmental instability. It reflects a compensatory strategy to reduce spinal loading during extension.

Clinical Relevance

Though not exclusive to instability, Gower’s Sign raises suspicion for lumbar motor control deficits or underlying hypermobility when found in adults with mechanical back pain.

Instability Catch

Instability Catch refers to a sudden, unplanned deviation in spinal movement, such as lateral bending or rotation, that occurs during forward flexion or return to extension.

Method

• Instruct the patient to bend forward from a standing position and then return to the upright position.
• Observe the movement path closely for any abrupt jerks, wobbles, or changes in direction.

Interpretation

A positive test is indicated by

• A sudden “catch” or uncontrolled deviation mid-movement
• Patient reports of sharp pain or a sense of giving way during the motion

Clinical Relevance

This test reflects poor segmental control or dynamic instability of the lumbar spine. It is most useful when interpreted alongside other signs of altered motor coordination.

Reversal of Lumbopelvic Rhythm

What is Lumbopelvic Rhythm

Lumbopelvic rhythm refers to the natural, coordinated movement between the lumbar spine and pelvis (via the hip joints) during bending and straightening motions, such as forward flexion and trunk extension.

The rhythm works like this

• During forward flexion, the lumbar spine flexes first, followed by anterior pelvic tilt and hip flexion
• During return to upright (extension)- the lumbar spine extends first, and then the pelvis tilts posteriorly, and the hips extend

This coordinated sequencing allows smooth, efficient movement and distribution of mechanical loads across the spine and hips.

This test evaluates this coordinated sequencing

Method

• Ask the patient to bend forward at the waist, then return to standing.
• Observe the sequence of movement during the return phase.

Interpretation

A reversal of rhythm is present when the patient initiates return by bending the knees or tilting the pelvis anteriorly first before lumbar extension

This indicates an altered or compensatory movement pattern, often used to avoid triggering pain or loading unstable segments.

Clinical Relevance

A positive finding suggests a loss of normal motor control or the presence of segmental stiffness/inhibition due to pain. It is commonly seen in patients with lumbar instability or chronic mechanical back pain.

Posterior Shear Test

This test is used to assess segmental pain provocation and potential hypermobility by applying an anterior shear force through the spinous process of the lumbar vertebrae.

Method

The patient lies in a relaxed prone position on the examination table.

• The examiner applies a gentle anterior pressure on the spinous process of a lumbar vertebra using a thumb or hypothenar contact.
• Each lumbar level is tested sequentially.

Interpretation

A positive test is indicated by:
• Reproduction of the patient’s familiar pain
• Pain localized to a specific lumbar segment

Clinical Relevance

Pain elicited during this passive movement suggests segmental instability or irritation, often due to excessive shear forces acting on an unstable motion segment.

Prone Instability Test

This test differentiates between pain caused by passive segmental structures and pain that is modulated by active muscular stabilization. It is commonly used to detect functional (dynamic) lumbar instability. [2]

Method

• The patient lies prone on the edge of an examination table, with the torso supported and legs hanging off, feet touching the floor.
• The examiner applies a posterior-to-anterior pressure on the lumbar spinous processes.
• If pain is reproduced, the patient is asked to lift their legs slightly off the floor (activating lumbar extensors), and the examiner repeats the pressure.

Interpretation

• A positive test is indicated by the presence of pain in the relaxed position that subsides when the legs are lifted.
• This indicates that active muscular engagement stabilizes the segment, reducing symptoms.

Clinical Relevance

This test is considered one of the more specific indicators of dynamic instability. It reflects the spine’s ability to self-stabilize through muscular control and helps identify patients who may respond well to motor control–based rehabilitation.

H and I Tests

These tests are designed to assess movement-specific instability by isolating motion along the horizontal (H) and vertical (I) planes. They help differentiate between general stiffness, directional movement control deficits, and pain linked to instability.

H Test (Horizontal Displacement Test)

The H movement is the first component of the H and I stability tests.

• The patient is positioned near the middle of the H while in their typical resting position.
• The side that is pain-free is tried first.
• The patient is asked to flex their lumbar side as much as possible, with assistance from the clinician (the side of H).
• Still in lateral flexion position, the patient is instructed to shift into extension (the back of the H) and then flexion (the front of the H).
• After that, the patient returns to neutral
• The same movements are repeated on the other side.

** Remember – First sidebend on one side then flex, extend an repeat on other sidebend

I Test

It is the second part of H/I test

• The patient stands in a typical resting posture.
• The patient forward flexes the lumbar spine until the hips begin to move
• This forms the upper portion of I.
• While still in flexion, the patient is asked to bend to one side and then side bend to the other
• The maneuver is repeated with the patient in extension

** Remember – First flex and then sidebend both ways, repeat in extension

Interpretation

H test

• Pain or movement difficulty during lateral shifting may indicate segmental instability, particularly in side gliding or shear control.
• Asymmetry between left and right shift can also suggest unilateral dysfunction.

I test

• Pain provoked specifically during this movement path, especially if absent in the H test, suggests vertical segmental loading issues.
• This helps narrow down which direction of movement is provoking instability.

Quadrant Test (Extension-Rotation Provocation Test)

This is a combined movement test used to provoke pain from facet joints or unstable segments by loading them in a compressed, rotated, and extended position.

Method

• The patient stands and extends the trunk, then rotates and laterally bends to the symptomatic side.
• The examiner may apply overpressure at end-range.

Interpretation:

• Localized pain suggests posterior element dysfunction (facet joint, capsule, or instability).
• Radiating pain may suggest nerve root involvement.

Clinical Relevance:

The quadrant test is a non-specific but sensitive test. It can help identify motion segments that require closer evaluation with other tests or imaging.

Interpretation and Limitations of Clinical Testing

Clinical tests for lumbar segmental instability provide valuable clues, especially when radiological findings are inconclusive or when symptoms suggest dynamic dysfunction. However, they must be interpreted within a broader clinical context.

No single test is diagnostic on its own. A combination of positive findings across multiple tests strengthens clinical suspicion.

These tests are best used in patients with

• Chronic mechanical low back pain
• Suspected functional or dynamic instability
• Normal or near-normal imaging findings

Limitations

• Low specificity: Many of these signs (e.g., Gower’s Sign, quadrant pain) may be seen in other lumbar pathologies such as discogenic pain or general deconditioning.
• Observer-dependent: Subtle findings (e.g., instability catch or rhythm reversal) may be missed without trained observation. [4]
• Pain modulation: Results can be influenced by the patient’s pain tolerance, fatigue, or psychosocial factors.
• Lack of standardization: There is variation in how some of these tests are performed and interpreted in clinical practice.

Conclusion

Use these tests as part of a comprehensive assessment that includes history, functional observation, and imaging. When several signs align with symptoms and segmental pain reproduction, lumbar instability becomes a more reliable working diagnosis.

FAQs

Can you have lumbar instability with a normal X-ray or MRI?

Yes. Many cases of functional or dynamic instability do not show up on standard imaging. Clinical tests help detect movement-based problems that aren’t visible radiographically.

Are these tests enough to diagnose lumbar instability?

No single test is conclusive. Diagnosis should be based on a combination of clinical findings, history, physical tests, and imaging when appropriate.

Is lumbar instability always painful?

Not necessarily. Some patients may have segmental hypermobility without symptoms, while others may experience pain with even mild instability.

What if only one lumbar instability test is positive?

A single positive test doesn’t confirm instability. Multiple aligned signs increase diagnostic confidence.

Can these tests guide treatment?

Yes. Positive findings on tests like the Prone Instability Test can help guide rehabilitation approaches focused on motor control and segmental stabilization.

References

1. Panjabi MM.Clinical spinal instability and low back pain. J Electromyogr Kinesiol. 2003;13(4):371-379 [Link]
2. Alqarni AM, Schneiders AG, Hendrick PA. Clinical tests to diagnose lumbar segmental instability: a systematic review. J Orthop Sports Phys Ther. 2011;41(3):130-140. [Pubmed]
3. Physiopedia. (n.d.). Lumbar Instability. Physiopedia. Retrieved May 11, 2025, from https://www.physio-pedia.com/Lumbar_Instability
4. Musculoskeletal Key. (n.d.). Lumbar Spine. Retrieved May 11, 2025, from https://musculoskeletalkey.com/lumbar-spine-3/
5. Rabin A, Kozol Z, Geffen Y, et al. Intertester reliability of clinical examination tests for lumbar segmental instability. J Manipulative Physiol Ther. 2013;36(1):26-33. [Link]