The Spine Lateral Flexion Test measures side-bending movement of the trunk and spine. It can be recorded using an inclinometer, tape measure, fingertip-to-thigh distance or another standardised method. The result helps monitor spinal movement and symptoms over time, but it should be interpreted with pain response, hip shift, trunk rotation, movement quality and related spine ROM findings.
A client may report stiffness when side-bending, reaching sideways, rotating during sport or moving in and out of loaded positions. Another client may appear to side-bend more easily to one side but compensate by rotating the trunk or shifting the hips.
The Spine Lateral Flexion Test helps quantify side-bending movement and compare left and right sides. Because the movement can include thoracic, lumbar, pelvic and hip contribution, method consistency is essential.
Test name: Spine Lateral Flexion Test
Purpose: Measure side-bending ROM
Movement: Trunk/spine lateral flexion
Joint/body region: Thoracic spine, lumbar spine, pelvis and trunk depending on method
Plane: Frontal plane
ROM type: Active ROM
Score: Degrees, distance or side-to-side comparison
Equipment: Inclinometer, smartphone inclinometer, tape measure or Measurz ROM workflow
Best used with: Spine flexion, spine extension, spine rotation, hip ROM, shoulder ROM and functional movement testing
Key limitation: Hip shift, trunk rotation and shoulder movement can affect the result
The Spine Lateral Flexion Test measures how far the client bends the trunk to the left or right. It can be assessed using a degree-based method or a distance-based method.
Common methods include:
Single or dual inclinometer measurement
Tape measure or fingertip-to-thigh distance
Photographic measurement
Smartphone inclinometer measurement
Standardised movement observation
The chosen method should be recorded clearly and repeated consistently.
The test is used to establish baseline side-bending movement, compare sides and monitor change over time.
It may help inform:
Spinal mobility programming
Side-to-side movement comparison
Sport movement assessment
Pain and symptom monitoring
Functional reaching assessment
Progress tracking across sessions
The test may measure:
Trunk side-bending range
Thoracolumbar lateral flexion
Side-to-side movement difference
Pain response
Symptom location
Hip or pelvic contribution
Trunk rotation compensation
Movement confidence
It does not explain the cause of reduced side bending on its own.
Spine lateral flexion is usually assessed actively. The client bends sideways under their own control.
Passive spinal side-bending is not usually used as a simple ROM tracking method and should be recorded separately if performed as part of a specific professional assessment.
This test may be useful for gym clients, field sport athletes, runners, golfers, swimmers, older adults, dancers and anyone where trunk side-bending, reaching or rotational movement is relevant.
Inclinometer or smartphone inclinometer
Tape measure if using distance method
Pain scale
Measurz for recording ROM, pain and symptoms
Optional video
Optional foot position marker
Position the client standing tall with feet in the selected stance. Record stance width and foot position.
The arms may rest by the sides or follow a standardised position. Use the same position each time.
Stand behind or in front of the client to observe trunk rotation, pelvic shift and shoulder movement.
Start from an upright posture with weight evenly distributed.
No manual stabilisation is usually required, but the professional should monitor hip shift and pelvic movement.
Ask the client to side-bend toward one side as far as comfortably possible without rotating or leaning forward/backward.
For inclinometry, use the selected thoracic and lumbar landmarks according to your method. For fingertip-distance methods, mark or record the start and end fingertip positions consistently.
Place the inclinometer consistently at the chosen landmarks. Record device and landmarks.
Ask about pain, stiffness, stretch, symptom location, symptom spread and whether symptoms are familiar.
Stop if symptoms increase sharply, dizziness occurs, balance is unsafe or the movement is not tolerated.
Record side, method, score, pain score, symptom location, movement quality, hip shift, trunk rotation and compensation.
One to three trials may be used. Record best, average or selected trial consistently.
Use the same stance, arm position, device, landmarks, instructions and endpoint each session.
The result may be recorded in degrees or distance.
A larger angle or greater distance may indicate more side-bending movement under the selected setup. Interpretation is often most useful when comparing left and right sides or baseline to retest.
Interpretation is stronger when paired with:
Pain score
Symptom location
Spine rotation
Spine flexion and extension
Hip movement
Shoulder movement
Functional movement findings
Movement quality and compensation
The result does not explain the cause of movement difference on its own.
Evidence level: Level 3 — values depend strongly on method and region measured.
Because lateral flexion can be measured using different tools and landmarks, universal norms are difficult to apply.
Practical benchmarks:
Compare left and right
Track baseline to retest
Use the same device and method
Record pain at end range
Record hip shift and trunk rotation
Interpret with related spine and functional findings
A 2021 study examining inter-rater reliability of tape measure and goniometer methods for thoracolumbar ROM supports the need for consistent training, landmarks and measurement method when assessing spine ROM. (sciencedirect.com)
A 2023 study found that smartphone, bubble inclinometer and universal goniometer methods can quantify thoracic spine active ROM, but reliability and validity vary by tool and movement. (pmc.ncbi.nlm.nih.gov)
Common errors include allowing trunk rotation, changing stance, inconsistent arm position, measuring shoulder slide instead of trunk movement, not recording symptoms, inconsistent landmarks and comparing different methods directly.
Limitations include hip shift, pelvic movement, shoulder position, pain, fear, warm-up, body shape and method differences.
Use spine lateral flexion ROM to monitor side-bending tolerance, track symptoms, compare sides and guide mobility or functional movement programming.
In Measurz, record baseline spine lateral flexion using the selected method. Record side tested, degrees or distance, device used, landmarks, pain score, symptom location, movement quality, hip shift, trunk rotation and confidence.
Track progress across sessions and compare with spine flexion, extension, rotation, hip ROM and relevant functional movement findings.
Spine Flexion Test
Spine Extension Test
Spine Rotation Test
Hip Abduction Test
Hip Adduction Test
Shoulder Flexion Test
Gait Assessment
Functional Reach Test
It measures side-bending movement of the trunk and spine using a standardised method.
Not exactly. It is a practical side-bending measure but can include shoulder, trunk, hip and pelvic movement.
Record side, method, score, pain, symptoms, device, landmarks and compensation.
No. It provides movement and symptom information but does not diagnose a condition.
Use the same stance, arm position, device, landmarks and endpoint each session.
Spine lateral flexion measures side-bending movement.
Method choice must be recorded.
Hip shift and trunk rotation can affect results.
Side-to-side comparison is often useful.
Measurz should capture score, method, pain, symptoms and movement notes.
Clarkson, H. M. (2020). Musculoskeletal assessment: Joint range of motion, muscle testing, and function (4th ed.). Wolters Kluwer.
Coulter, E. H., et al. (2021). Interrater reliability of spine range of motion measurement using a tape measure and goniometer. Journal of Chiropractic Medicine, 20(3), 138–147. Needs verification.
van Baalen, G. H., et al. (2023). Reliability and validity of a smartphone device and clinical tools for thoracic spine mobility assessment. Sensors, 23(17), 7622.
