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Straight leg raise
Straight leg raise
Straight leg raise
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Straight leg raise
Straight leg test sometimes used to help diagnose a lumbar herniated disc. Usually the legs are raised alternatingly, not simultaneously.
Purposedetermine if a herniated disc is the cause of leg pain

The straight leg raise is a test that can be performed during a physical examination, with the leg being lifted actively by the patient or passively by the clinician. If the straight leg raise is done actively by the patient, it is a test of functional leg strength, particularly the rectus femoris element of the quadriceps (checking both hip flexion and knee extension strength simultaneously). If carried out passively (also called Lasègue's sign, Lasègue test or Lazarević's sign), it is used to determine whether a patient with low back pain has an underlying nerve root sensitivity, often located at L5 (fifth lumbar spinal nerve). The rest of this article relates to the passive version of the test.

Technique

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With the patient lying down on their back on an examination table or exam floor, the examiner lifts the patient's leg while the knee is straight.[citation needed]

A variation is to lift the leg while the patient is sitting.[1] However, this reduces the sensitivity of the test.[2]

In order to make this test more specific, the ankle can be dorsiflexed and the cervical spine flexed. This increases the stretching of the nerve root and dura.[3]

Interpretation

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If the patient experiences sciatic pain, and more specifically pain radiating down the leg (radiculopathy), when the straight leg is at an angle of between 30 and 70 degrees, then the test is positive and a herniated disk is a possible cause of the pain.[4] A negative test suggests a likely different cause for back pain.[citation needed]

A positive straight leg test reproduces radiating leg pain. If it only causes back pain, then the test is negative.

A meta-analysis reported the straight-leg test as having:[5]

If raising the opposite leg causes pain (cross or contralateral straight leg raising):

  • sensitivity 29%
  • specificity 88%

Lasègue's sign

[edit]

Lasègue's sign was named after Charles Lasègue (1816–1883).[6] In 1864 Lasègue's medical student J.J. Forst described the signs of developing low back pain while straightening the knee when the leg has already been lifted. In 1880 Serbian doctor Laza Lazarević described the straight leg raise test as it is used today, so the sign is often named Lazarević's sign in Serbia and some other countries.[7]

See also

[edit]

References

[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Straight leg raise

View on Grokipedia
from Grokipedia
The straight leg raise (SLR) is a clinical maneuver used in . It serves as a diagnostic test to identify lumbosacral irritation, commonly associated with lumbar disc herniation or , and as a therapeutic exercise to strengthen the flexors, , and core while improving lower extremity . As a diagnostic tool, known as the Lasègue sign, the SLR helps detect in patients with and leg symptoms. The crossed straight leg raise variant provides enhanced specificity for compression. Therapeutically, the SLR is prescribed after or and for conditions like injuries to aid recovery and restore function.

Overview

Definition and Purpose

The straight leg raise (SLR) test is a fundamental neurological maneuver performed with the patient in a , in which the examiner passively elevates the patient's fully extended lower limb to assess tension and irritation of the lumbosacral nerve roots. This test, also known as the Lasegue test, specifically evaluates the and associated lumbosacral roots by reproducing radicular symptoms, such as pain radiating down the leg, to identify underlying neural compression or . The primary purpose of the SLR test is to detect lumbar radiculopathy, particularly arising from conditions like herniation or , where mechanical compression or inflammation affects nerve function. By eliciting pain in a dermatomal distribution along the posterior and calf, the test helps differentiate from localized musculoskeletal issues, guiding clinicians toward appropriate or referrals. A positive result typically occurs when is provoked between 30° and 70° of flexion, indicating dural or sensitivity. Anatomically, the SLR stretches the L4-S1 nerve roots and the , as the sciatic nerve's limited excursion—normally 4-6 mm—becomes restricted by adhesions or compression in the spinal foramina during . below 70° of specifically suggests irritation of these structures, often due to at the L4-L5 or L5-S1 levels, rather than hamstring tightness alone. In clinical practice, the SLR is routinely employed in , , orthopedics, and settings as an initial screening tool for patients presenting with accompanied by leg symptoms, facilitating early identification of nerve-related pathologies. It serves as a non-invasive bedside assessment, often supplemented briefly by like Lasègue's sign to enhance detection of root tension.

Historical Background

The straight leg raise (SLR) test originated in the late as a clinical maneuver to assess irritation. Serbian physician Lazar K. Lazarević first described the test in 1880, noting that elevating the leg with the knee extended in a elicited due to stretching of the , and he quantified the angle at which occurred. This observation built upon earlier descriptions of in by French clinician Ernest-Charles Lasègue in 1864, who reported that symptoms worsened upon standing or walking but did not detail the leg elevation technique. In 1881, Jean-Joseph Forst, a student of Lasègue, formalized the SLR in his doctoral thesis, incorporating knee flexion and extension variations and dedicating the work to his mentor, leading to the test's common attribution as Lasègue's sign despite Lasègue not authoring the description himself. Early development of the SLR occurred amid growing interest in tension signs during the , with clinicians recognizing that passive in positions could provoke radicular symptoms indicative of . By the 1880s, studies, such as those by Beurmann in 1884, refuted initial theories attributing pain to pressure rather than neural stretch, solidifying the test's basis in . The maneuver gained refinements, including the crossed SLR variant introduced by Polish neurologist Izydor Fajersztajn-Krzemicki in , which involved raising the unaffected to elicit contralateral pain. These advancements positioned the SLR as a key diagnostic tool for lumbosacral by the early , integrating it into routine neurological examinations as surgeons began linking to spinal pathologies beyond mere inflammation. The SLR's evolution continued through the mid-20th century, becoming a staple in standardized neurological assessments. By the 1940s, it was routinely included in clinical protocols for evaluating and , with texts emphasizing its role in identifying compression. Russell N. DeJong's influential The Neurologic Examination, first published in 1950 and revised in subsequent editions, formalized the test's procedure within comprehensive neurologic evaluations, underscoring its simplicity and bedside utility. Key milestones in the late involved its association with advanced imaging; the advent of computed tomography in the 1970s and (MRI) in the 1980s-1990s transformed the SLR from a primary diagnostic standalone to a confirmatory adjunct, correlating positive findings with disc herniations visible on scans and improving specificity for surgical candidacy. Today, it serves as a screening tool for , often paired with imaging for definitive diagnosis.

Technique

Standard Procedure

The straight leg raise (SLR) test is a passive neurodynamic maneuver used to evaluate for lumbosacral irritation in patients presenting with lower back pain and possible . Patient preparation involves positioning the individual on a firm examination table, with both hips and knees fully extended, the spine in a neutral position, and the head resting comfortably on the table or a small to facilitate relaxation. The examiner first explains the test procedure, its purpose, and what sensations the patient may experience, obtaining verbal consent and ensuring ; a clinical chaperone should be present if the examination involves a of the opposite gender or as per institutional policy. The examiner stabilizes the patient's by placing one hand on the contralateral to minimize posterior tilting or rotation during elevation. With the other hand grasping the or posterior aspect of the , the tested leg is passively lifted into flexion while maintaining full extension and a neutral ankle position, performed slowly and steadily to allow gradual tensioning of neural structures. Both legs are tested sequentially, starting with the unaffected side if applicable, to establish a baseline comparison. The angle of hip flexion is observed and recorded, using a goniometer aligned with the if precise quantification is needed, noting the degree at which any symptoms such as , tingling, or numbness in the lower limb first appear. The maneuver is terminated immediately upon symptom onset or patient request, or continued to 70-90 degrees of hip flexion if no radicular symptoms occur; a normal result permits full elevation to this range without lower limb pain or , limited primarily by flexibility. Safety considerations include contraindications for patients with acute spinal injuries, severe preexisting pain, inability to lie supine, or significant joint deformities that could exacerbate symptoms. The examiner continuously monitors for compensatory movements, such as unintended knee flexion or pelvic rocking, and aborts the test if excessive discomfort arises to prevent harm.

Variations and Modifications

The straight leg raise (SLR) test can be adapted into various positions to enhance specificity for different neural structures, differentiate neural from musculoskeletal sources of pain, or accommodate patient limitations such as inability to lie supine. These modifications maintain the core principle of applying tension to neural tissues while altering body positioning to target specific nerve roots or improve patient comfort. In the seated straight leg raise, also known as the Bechterew test, the patient sits upright on the edge of the examination table with legs dangling and s initially flexed to 90 degrees; the examiner then passively extends the of the affected while stabilizing the to prevent hip flexion. This variation replicates the neural tension of the SLR but is particularly useful for patients who experience anxiety when lying down or have conditions preventing positioning, such as acute or respiratory issues, and studies show it yields equivalent results in detecting radicular symptoms at similar hip flexion angles. Pain reproduction in the low back or during extension indicates lumbosacral irritation, comparable to the standard test. The prone knee bend test, sometimes integrated into broader femoral nerve assessments, involves positioning the patient with the knee passively flexed to 90 degrees by the examiner while keeping the hip neutral or slightly extended. This adaptation helps differentiate involvement from isolated muscle tightness; radiating distally suggests neural irritation at L4 or higher, whereas localized posterior thigh discomfort without radiation points to muscular , as the minimizes tension while stressing the hamstrings and upper lumbar roots. It is especially valuable when testing is inconclusive for posterior leg pain sources. The reverse straight leg raise, also referred to as the stretch or Ely test, requires the patient to lie prone while the examiner lifts the extended from the table, maintaining extension and gradually adding extension if tolerated. This targets the and L2-L4 nerve roots, reproducing anterior thigh or in cases of upper radiculopathy or femoral neuropathy, contrasting with the lower focus of the standard SLR. Positive findings here indicate distinct from lumbosacral disc issues, aiding in localization of compression. For special populations, such as elderly or obese patients, modifications include performing the test in a seated position to reduce strain from lying or using a lower initial leg raise angle (e.g., starting below 30 degrees) to account for reduced flexibility, stiffness, or body habitus that may limit full flexion. In rehabilitation settings, slings or supportive straps can assist passive leg elevation, allowing gradual progression while minimizing compensatory trunk movement and enhancing safety for those with mobility impairments. These adaptations prioritize and isolation of neural versus musculoskeletal without compromising diagnostic utility. A therapeutic variation of the straight leg raise is used in rehabilitation to strengthen the knee, particularly targeting the vastus medialis obliquus (VMO) muscle for improved patellar tracking. The patient lies down or sits with the affected leg straight, slowly raises the leg 20-30 cm off the ground with toes pointing up while focusing on inner thigh contraction, holds for 5 seconds, then slowly lowers it. This is performed in 3 sets of 10-15 repetitions daily.

Interpretation

Positive and Negative Results

A negative result in the straight leg raise (SLR) test occurs when there is no reproduction of , such as shooting, burning, or numbness in the leg, during elevation up to 70-90 degrees of hip flexion with the knee extended. This outcome typically suggests that the patient's is not related to lumbosacral irritation, pointing instead toward musculoskeletal causes like non-nerve-related strain. In contrast, a positive SLR test is indicated by the reproduction of the patient's familiar in the affected leg, occurring specifically between 30 and 70 degrees of flexion. This often follows dermatomal patterns, such as along the L5-S1 distribution in the posterior leg, and is distinct from localized back or buttock discomfort. elicited above 70 degrees is generally attributed to hamstring tightness rather than neural involvement, and radicular symptoms are absent in the contralateral leg unless a crossed SLR variant is present. Enhancing the test with foot dorsiflexion can increase sensitivity for detecting subtle tension. Clinically, a positive SLR result warrants further evaluation, including referral to a specialist or advanced imaging such as MRI, to confirm underlying pathology. When combined with neurological deficits like or , it correlates with a high likelihood of disc herniation. False positives are common in non-specific , where symptoms may mimic due to other causes like issues or soft tissue strain.

Diagnostic Accuracy and Limitations

The straight leg raise (SLR) test demonstrates high sensitivity but low specificity for detecting disc herniation with . A of 16 studies involving over 1,700 patients reported a pooled sensitivity of 91% (95% CI 89%-93%) and specificity of 26% (95% CI 18%-35%) when using pain reproduction below the as the positive criterion, compared against or surgical confirmation as the reference standard. The positive likelihood ratio for a positive SLR is approximately 1.2, indicating modest ability to rule in the condition, while the negative likelihood ratio of approximately 0.3 supports its utility in ruling out disc herniation when absent. Specificity improves when the SLR is combined with neurological findings such as sensory deficits, elevating the overall diagnostic value in . For instance, the presence of SLR positivity alongside sensory abnormalities or enhances confidence in diagnosis compared to SLR alone. This evidence is supported by systematic reviews and clinical guidelines, including the 2007 joint guideline from the and American Pain Society, which endorses the SLR as a key component of the physical exam for suspected in settings. Updated meta-analyses through 2023 confirm its consistent utility in for initial screening, though with persistent emphasis on its role within a broader rather than isolation. Despite these strengths, the SLR has notable limitations that can compromise its reliability. Its low specificity often results in over-diagnosis, as positive findings may reflect non-specific musculoskeletal pain rather than true compression, leading to unnecessary imaging or interventions. Patient factors further influence test performance; for example, advancing age reduces sensitivity to as low as 33% in those over 60, increasing false negatives, while conditions like may alter pain reporting due to associated fear of movement or reduced flexibility. Additionally, the test is less effective for central or non-radicular , where mechanosensitivity is not primarily involved. To mitigate these limitations, the SLR is most effective when used as part of a clustered examination incorporating other neurological assessments, such as reflexes and muscle strength testing, which collectively improve diagnostic precision over standalone application.

Bragard's Test

Bragard's test is a modification of the straight leg raise (SLR) test used to evaluate neural tension, where passive dorsiflexion of the ankle during leg elevation between 30 and 70 degrees exacerbates or induces in the lower limb, signifying dural or lumbosacral involvement. This augmentation heightens the detection of neural tension, distinguishing it from the baseline SLR maneuver. The procedure is conducted after performing the initial SLR to identify the angle of pain onset, typically the patient's threshold. At this point, the examiner passively dorsiflexes the foot while maintaining the elevated leg position, observing for any increase in radicular symptoms such as shooting along the sciatic distribution. If intensifies with dorsiflexion, the test is considered positive, confirming rather than mere mechanical limitation. Anatomically, dorsiflexion during SLR increases tensile stress on the sciatic nerve and its lumbosacral roots (L4-S3), as well as the dura mater, by further elongating the neural pathway and pulling the dura caudally, laterally, and anteriorly toward the site of potential compression, such as at the greater sciatic notch. This added tension mimics or amplifies the effects of nerve root impingement, often from disc herniation, without significantly affecting non-neural structures. Clinically, Bragard's test offers greater specificity for compression compared to the standard SLR. A study reported sensitivity of 69% and specificity of 67% using electrodiagnosis as the reference standard, aiding in decisions for or interventions like epidural injections. The test was described by German physician Karl Bragard in 1929, building on earlier SLR descriptions. This test effectively differentiates neural from non-neural pain sources; for instance, worsens with dorsiflexion due to dural involvement, whereas strain or sacroiliac dysfunction produces localized discomfort that remains unchanged or only slightly affected by the maneuver.

Crossed Straight Leg Raise

The crossed straight leg raise (XSLR) test, also known as the Fajersztajn sign, is a variant of the straight leg raise maneuver that is considered positive when passive elevation of the unaffected leg reproduces in the symptomatic leg, typically indicating central disc herniation or severe lumbosacral compression. The procedure follows the standard straight leg raise protocol but is performed on the pain-free side, with the patient and the examiner passively flexing the while keeping the extended; pain radiating to the affected side at an angle of less than 40 degrees is diagnostic and suggests a high likelihood of a surgically treatable due to significant root impingement. Anatomically, the test elicits pain through tension transmitted across the midline via the dural sheath and interconnected lumbosacral nerve s (primarily L5-S1), where a central herniation compresses the contralateral during ipsilateral elevation. Clinically, the XSLR demonstrates higher specificity (up to 90%) compared to the unilateral straight leg raise for identifying disc herniation with involvement and is observed in approximately 25-30% of confirmed lumbar herniated disc cases, often signaling bilateral or severe pathology that may warrant surgical intervention. Supporting evidence from neurosurgical studies spanning the to , including systematic reviews and cohort analyses, shows a strong between positive XSLR results and MRI-confirmed central herniations (positive predictive value approaching 97% for disc ), as well as favorable surgical outcomes such as 91% return to work post-laminectomy in affected patients.

References

  1. https://www.ncbi.nlm.nih.gov/books/NBK545299/
  2. https://www.verywellhealth.com/how-to-the-straight-leg-raise-2696526
  3. https://www.ncbi.nlm.nih.gov/books/NBK539717/
  4. https://pubmed.ncbi.nlm.nih.gov/26391412/
  5. https://pmc.ncbi.nlm.nih.gov/articles/PMC8046483/
  6. https://www.acpjournals.org/doi/10.7326/0003-4819-137-7-200210010-00010
  7. https://www.mdpi.com/2073-8994/12/6/927
  8. https://bmcneurol.biomedcentral.com/articles/10.1186/1471-2377-10-75
  9. https://pmc.ncbi.nlm.nih.gov/articles/PMC2505147/
  10. https://pmc.ncbi.nlm.nih.gov/articles/PMC6162033/
  11. https://pubmed.ncbi.nlm.nih.gov/6444765/
  12. https://www.ccjm.org/content/ccjom/73/9/839.full.pdf
  13. https://www.joionline.net/library/vmo-strength-exercises/
  14. https://www.posturedirect.com/vmo-exercises/
  15. https://www.physio-pedia.com/Straight_Leg_Raise_Test
  16. https://www.orthobullets.com/spine/2035/lumbar-disc-herniation
  17. https://pafmj.org/index.php/PAFMJ/article/download/200/133
  18. https://pubmed.ncbi.nlm.nih.gov/10788860/
  19. https://www.acpjournals.org/doi/10.7326/0003-4819-147-7-200710020-00006
  20. https://pmc.ncbi.nlm.nih.gov/articles/PMC10696343/
  21. https://pubmed.ncbi.nlm.nih.gov/20709300/
  22. https://www.jcdr.net/article_fulltext.asp?issn=0973-709x&year=2017&month=May&volume=11&issue=5&page=RG01&id=9794
  23. https://www.researchgate.net/publication/316958805_Lasegue%27s_Sign
  24. https://pubmed.ncbi.nlm.nih.gov/29628807/
  25. https://www.physio-pedia.com/Bragard%27s_Sign
  26. https://pubmed.ncbi.nlm.nih.gov/469603/
  27. https://www.physio-pedia.com/Crossed_Straight_Leg_Raise_Test
  28. https://www.aliem.com/trick-of-trade-crossed-straight-leg/
  29. https://academic.oup.com/bjs/article/108/Supplement_6/znab259.1002/6388831
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