Cervical rotation lateral flexion test: Procedure and evidence

Key takeaways

The cervical rotation lateral flexion test (CRLF test) is a passive screen for first rib hypomobility in patients with neck or arm symptoms.

A positive test means lateral flexion toward the shoulder is restricted after full cervical rotation, usually alongside the patient’s familiar arm or neck pain.

No validated sensitivity or specificity figures exist for the CRLF test. Lindgren et al. (1992) established near-perfect agreement between examiners, which is reliability rather than diagnostic accuracy.

The only study to test CRLF accuracy directly (Koppenhaver et al. 2022) found it did not predict who benefited from first and second rib manipulation.

Practice management software like Pabau keeps positioning, range-of-motion figures, and reproduced symptoms in one structured note you can compare at follow-up.

The cervical rotation lateral flexion test is a passive screen for first rib hypomobility. You rotate the neck away from the side you are testing. Then you bring the head toward the opposite shoulder and watch what the movement does.

It is usually shortened to the CRLF test. Physical therapists, chiropractors, and osteopaths use it when a patient reports neck pain with arm symptoms and the source is not obvious.

Plenty of sites quote sensitivity and specificity figures for this test. Those numbers do not exist in the literature. This guide covers the procedure, how to read the result, what the two relevant studies measured, and a free form for documenting it.

What is the cervical rotation lateral flexion (CRLF) test?

The CRLF test is an orthopedic assessment that combines cervical rotation with passive lateral flexion to judge first rib mobility. A restricted result points to first rib hypomobility, meaning the rib is not gliding freely as the neck moves. That restriction is one possible contributor to thoracic outlet syndrome (TOS), brachialgia, or cervical radiculopathy.

Isolated range-of-motion testing does not load the first rib in the same way. Rotating first takes the cervical spine to end range. The lateral flexion that follows has to come from the rib and the soft tissue around it. That is why the finding tells you something a plain lateral flexion measurement cannot.

Do not confuse it with the cervical flexion-rotation test (CFRT). The CFRT assesses upper cervical rotation at C1-C2 in patients with cervicogenic headache. Different structure, different question, different evidence base.

The craniocervical flexion test is a third test again, and it measures deep neck flexor endurance. Names this similar get mixed up often, and their numbers get swapped along with them. More on that further down the page.

• Primary clinical purpose: Screen for first rib hypomobility
• Conditions it is used around: Thoracic outlet syndrome, brachialgia, cervical radiculopathy
• Patient population: Neck pain, upper extremity pain, or neurological symptoms in the arm
• Examiner requirement: Training in passive assessment and end-feel interpretation

Whatever the result, it needs to reach the patient record in a form the next clinician can use. Degrees, end-feel, and the exact symptom reproduced all matter later.

Practice management software like Pabau can capture them while the patient is still in the room. Pabau Scribe, writes the note up from what you say during the appointment. The downloadable form above gives you the same fields on paper.

Relevant anatomy: Cervical spine and first rib

Knowing what the test loads makes the result easier to read. The cervical spine has seven vertebrae, and each contributes some rotation and some lateral flexion. The brachial plexus, subclavian artery, and subclavian vein all run through the thoracic outlet. That space is narrow, bounded by the clavicle, the first rib, and the scalenes.

The first rib forms the floor of that space. It should elevate and glide as the neck moves. When it stops doing that, the neurovascular bundle above it has less room, and the patient may report arm pain, numbness, or weakness. That picture is what clinicians label thoracic outlet syndrome.

• Cervical rotation: Mostly C1-C2, which is what turns the head side to side
• Lateral flexion: Distributed across C3-C7 as the head moves toward the shoulder
• First rib mobility: The rib must elevate and medialize during lateral flexion, and hypomobility blocks that
• Scalene muscles: The anterior and middle scalenes tie the cervical spine to the first rib, so tightness here restricts rib movement
• Neurovascular structures: The plexus, artery, and vein sit against the rib and lose space when it is held down

So the CRLF test asks a simple mechanical question. Can the first rib move while the cervical spine is already at end-range rotation? Restriction suggests it cannot, and familiar arm pain during the movement raises the chance that the thoracic outlet is involved.

How to perform the CRLF test: Step-by-step procedure

Run the test with the patient seated or supine. Seated suits most practices, because it is easier to stabilize the shoulders and watch for compensation. These five steps keep the technique consistent between clinicians and between visits.

1. Position the patient. Sit them upright with the arms resting and the neck relaxed. If you work supine, support the head on a small pillow.
2. Rotate away from the test side. To test the right first rib, rotate the head to the left. Take rotation to end range with gentle passive over-pressure, and stabilize the shoulders so the trunk does not follow.
3. Add passive lateral flexion. From that rotated position, guide the head toward the opposite shoulder. Move slowly and ask the patient to report arm pain, neck pain, tingling, or numbness as you go.
4. Assess end-feel and range. Note whether the movement runs out smoothly or stops abruptly. Estimate the degrees achieved, using roughly 45 degrees from vertical as normal lateral flexion.
5. Check for symptom reproduction. The most useful finding is the patient’s own presenting symptom appearing during the movement. Write down exactly which symptom returned and where the patient felt it.

Always repeat the test on the other side. Asymmetry is more informative than a single measurement, because normal cervical range of motion varies widely between people. The unaffected side gives you that patient’s own baseline to compare against.

Capturing both sides while the patient is still in front of you saves rework. Digital forms let you type the degrees, the end-feel, and the reproduced symptom straight into the record during the appointment.

Interpreting results: Positive, negative, and equivocal findings

Read the result from three things: how far lateral flexion travels, how it feels at the end, and whether the patient’s familiar symptoms return. A positive test does not diagnose thoracic outlet syndrome. It flags first rib hypomobility as a plausible contributor to what the patient is describing.

• Positive: Lateral flexion is clearly restricted after full rotation, short of the roughly 45 degrees you would expect and short of the opposite side. The patient’s usual arm or neck symptoms return, and a hard, abrupt end-feel supports the finding.
• Negative: Range is normal or close to it, the end-feel is soft, and nothing familiar is reproduced. First rib mobility is probably fine, so look elsewhere for the source.
• Equivocal: Restriction without symptoms, or symptoms without restriction. Add other tests, such as the upper limb tension tests or Adson’s maneuver, before you commit to an interpretation.

Resist reading more into a positive test than it can carry. TOS has neurogenic, arterial, and venous forms, and each presents differently. The CRLF test contributes one mechanical finding to a fuller cervical and upper extremity examination.

What the evidence shows

Only two studies matter here, and neither one gives you a sensitivity figure. Lindgren, Leino and Manninen (1992), writing in Archives of Physical Medicine and Rehabilitation, looked at whether two examiners reach the same CRLF result. They did, in all 23 patients, giving a kappa of 1.0.

The authors also checked their findings against cineradiography of first rib movement in a handful of those patients, and the results lined up. That is reliability plus a mechanical check. It is not diagnostic accuracy, and the study reports no sensitivity, specificity, or likelihood ratios at all.

Diagnostic performance was tested once, three decades later. Koppenhaver et al. (2022) examined 50 patients with neck pain, then treated all of them with first and second rib manipulation. The CRLF result did not predict who improved. Age and sex were more useful predictors than the test itself.

Where do the quoted numbers come from, then? They belong to a different test. The cervical flexion-rotation test has published figures around 91% sensitivity and 90% specificity for upper cervical dysfunction in cervicogenic headache. Similar initials, similar body region, and the values drift across into CRLF articles.

Once you know that, the numbers are easy to spot. A CRLF figure with no study attached, or one credited to Lindgren, has been borrowed from the CFRT literature. Quoting it in a note or a referral letter puts a claim in the record that no paper supports.

None of this makes the test useless. It is quick, it needs no equipment, and two clinicians will agree on the answer. Use it to describe mobility and reproduce symptoms. Then let the treatment response, rather than a borrowed statistic, tell you whether the first rib was the problem.

Differential diagnosis considerations

Arm and neck pain has several plausible sources, and more than one can be present at once. Work through the alternatives before you settle on thoracic outlet involvement.

• Cervical radiculopathy: Nerve root compression at C5, C6, or C7, usually from disc herniation or osteophytes. Look for dermatomal pain, paresthesia, or weakness, and add Spurling’s test. Radiculopathy and first rib restriction can coexist, so treat both when both are present.
• Neurogenic thoracic outlet syndrome: Brachial plexus compression, and the most common form of TOS. Symptoms are diffuse rather than dermatomal. Confirming it means imaging, such as CT angiography or MRA, to rule out the vascular forms.
• Brachialgia: Arm pain of mixed origin involving the cervical spine, the shoulder girdle, or the outlet. A positive CRLF points you toward rib and scalene work. A negative one sends you back to the neck and shoulder.
• Shoulder pathology: Rotator cuff problems, acromioclavicular joint dysfunction, and scapular dyskinesis all mimic TOS. Shoulder-specific tests and a shoulder range of motion comparison separate them. Patients can have both, particularly overhead workers and athletes.
• Myofascial pain: Trigger points in the scalenes or pectoralis refer pain into the arm. Palpation reproduces it. First rib mobility is usually normal, so the CRLF test reads negative or equivocal.

The CRLF test earns its place inside a broader assessment. Combine it with the history, a neurological screen, imaging where indicated, and the response to your first few treatments.

How to document the CRLF test in clinical notes

Good documentation protects continuity of care, supports your reasoning, and holds up under insurance or medico-legal review. If your practice writes in SOAP note format, the test belongs in the objective section. Six elements cover it.

1. Position and preparation. Record whether the patient was seated or supine. Note any pain or guarding present before you started.
2. Procedure performed. One line is enough. “Cervical spine rotated away from the test side, then passive lateral flexion applied toward the opposite shoulder.” Add any trunk compensation you saw.
3. Range of motion. Give degrees for both sides, such as “right 38 degrees, left 43 degrees”. Name the asymmetry, and describe the end-feel as soft, firm, or hard.
4. Symptom reproduction. Write what the patient reported, in their words where possible. State clearly whether it matched the presenting complaint or was something new.
5. Interpretation. Say what you concluded and why, and keep the claim proportionate. “Restricted right CRLF with familiar forearm pain, consistent with first rib hypomobility contributing to symptoms.”
6. Plan and follow-up. Note the treatment, the reassessment date, and any referral for imaging or a specialist opinion.

The downloadable form above captures all six in the same order, which makes handovers between clinicians much less work. Whoever sees the patient next can find the earlier figures without reading the whole file.

How Pabau keeps rib mobility findings comparable

In most practices the CRLF result lands in a free-text note or on a paper chart. Degrees get written for one side only. End-feel gets skipped when the room is running late. Six weeks later, nobody can say whether the restriction improved.

Pabau replaces that with a form the clinician completes during the appointment. Fixed fields for left and right degrees, end-feel, and reproduced symptoms mean the same data is captured every time. Pabau Scribe can write the narrative part from what you said out loud while testing.

Because it all sits on one patient timeline, the reassessment starts with the earlier numbers already on screen. You can see 38 degrees become 42, and so can the patient. That comparison is also what a referral form needs, so writing one stops being a retyping job.

For practices with several clinicians, the win is consistency. Everyone documents the test the same way, whoever runs it. Audits, handovers, and insurance queries stop depending on one person’s note-taking habits.

Keep every CRLF assessment in one structured record

Pabau helps physical therapy, chiropractic, and osteopathy practices capture assessment findings, manage patient records, and track outcomes from intake through discharge.

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Conclusion

The CRLF test is worth keeping in your examination. It takes seconds, needs no equipment, and two trained clinicians will read it the same way. What it cannot give you is a diagnostic probability, because nobody has ever measured one for it.

So use it for what it does. Describe the mobility you found, record the symptom you reproduced, treat, and re-measure. Let the change between visits carry the clinical argument instead of a statistic borrowed from another test.

Download the free form above to standardize how your team records the test. If you would like to see how Pabau handles assessment forms, patient records, and outcome tracking in one place, book a demo.

Continue your research

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Need a recording sheet for a passive knee test? Quadriceps active test gives you the positioning prompts and a printable form.

Grading muscle response in a neurological caseload? Tardieu Scale explains the grades and gives you a form for recording them.

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