The Fajersztajn’s crossed sciatic sign is pain on the affected side of the lower limb elicited by lifting the extended opposite leg. It is a clinical indicator of sciatic nerve irritation, commonly due to lumbar disc herniation.

Pathophysiology

• Sciatic nerve irritation occurs when a herniated lumbar intervertebral disc compresses or inflames nerve roots, usually L5 or S1.

• Lifting the contralateral leg stretches the dural sac and nerve roots, producing tension that radiates pain along the distribution of the affected sciatic nerve.

• A positive crossed straight-leg raise suggests more severe nerve root compression than pain elicited by ipsilateral leg elevation alone.

Examination Technique

1. Patient Positioning: Patient lies supine on the examination table with both legs extended.

2. Maneuver:

   • Flex the hip of the unaffected (opposite) leg, keeping the knee fully extended.

   • Slowly raise the leg toward the chest.

3. Assessment:

   • Positive sign: Pain radiates down the affected leg, indicating nerve root irritation.

   • Compare with pain elicited by ipsilateral straight-leg raise.

   • Document intensity, location, and distribution of pain.

Clinical Utility

• Diagnosis of lumbar disc herniation: More specific than ipsilateral straight-leg raise.

• Assessment of nerve root involvement: Helps localize affected roots (typically L5 or S1).

• Severity indicator: Positive crossed sign correlates with more significant compression or nerve irritation.

Differential Diagnosis

Pediatric considerations

• Rarely performed; sciatic nerve irritation uncommon in children.

• May be used in older adolescents with disc pathology.

Geriatric considerations

• Useful in older adults with degenerative disc disease.

• Exercise caution with fragile spine or comorbid conditions.

Limitations

• Requires patient cooperation and relaxation.

• False negatives can occur if pain is mild or if patient guards the limb.

• Not specific for disc herniation in isolation—should be interpreted with imaging and other clinical findings.

Patient counseling

• Explain the purpose: to identify nerve irritation causing leg pain.

• Inform the patient that mild discomfort is expected during testing.

• Advise against sudden movements to prevent exacerbation of symptoms.

• Recommend follow-up for further evaluation if positive.

Conclusion

The Fajersztajn’s crossed sciatic sign is a valuable clinical tool for detecting sciatica due to lumbar disc herniation, particularly when more severe nerve root involvement is suspected. Proper technique and interpretation aid in diagnosis, localization, and management planning.

References

1. Fajersztajn M. Über die Bedeutung der Kreuzzeichen bei Ischias. Zeitschrift für klinische Medizin. 1901;46:141–144.

2. Deyo RA, et al. Diagnostic evaluation of low back pain: Clinical evaluation and imaging. N Engl J Med. 2002;347:108–115.

3. Magee DJ. Orthopedic Physical Assessment. 7th ed. Philadelphia, PA: Elsevier; 2021.

4. Hoppenfeld S, deBoer P. Physical Examination of the Spine and Extremities. 2nd ed. New York: Appleton & Lange; 2000.