Bowstring Sign

The Bowstring Sign, also known as the popliteal compression test or Posterior Tibial Nerve Stretch Sign, is used to evaluate lumbosacral nerve irritation in suspected sciatica. This test is considered a modified version of the Straight Leg Raise (SLR) and helps confirm neural tension and compression of the sciatic nerve [1].

The test is particularly useful for identifying neurodynamic restrictions related to lumbar nerve root compression, which may occur with lumbar disc herniation, foraminal stenosis, or other radiculopathies.

Test Procedure

Patient Position

• The patient lies supine on the examination table without a pillow, maintaining a neutral spinal alignment.

Examiner Position

• The examiner stands at the side of the leg being tested, facing the patient.

Step-by-Step Execution

1. Perform a Straight Leg Raise (SLR)

   • The examiner lifts the patient’s leg with the knee fully extended.

   • The leg is raised until the patient reports pain along the lumbosacral dermatome distribution, or until maximum flexion is reached.

2. Reduce Pain with Knee Flexion

   • When pain occurs, the examiner slightly flexes the knee (~20°), which usually reduces the discomfort.

3. Apply Popliteal Pressure (Bowstring)

   • Using the thumb, the examiner applies firm pressure to the sciatic nerve within the popliteal fossa (over the tibial nerve).

   • If this reproduces the patient’s sciatica, the test is considered positive [2].

4. Bilateral Testing

   • Always begin with the non-symptomatic side for comparison.

Interpretation of Results

• Positive Test: Reproduction of sciatic pain with pressure in the popliteal fossa → indicates neural compression or irritation.

• Negative Test: No pain provocation.

Diagnostic Validity and Evidence

• The Bowstring Sign is a modification of the SLR test.

• A 2020 study recommends combining the Bowstring Sign with the Femoral Nerve Tension Test, Slump Test, and SLR to improve sensitivity and specificity in diagnosing sciatica [4].

• No standalone psychometric data exist for the Bowstring Sign, but it remains widely used as part of a comprehensive neurological evaluation.

Clinical Relevance

• The Bowstring Sign is a quick and simple neurodynamic test for identifying lumbosacral nerve compression, particularly associated with sciatica and radiculopathy.

• It should always be performed alongside other neurological tests and clinical findings.

• A positive result strongly suggests sciatic nerve involvement, but imaging may be required for confirmation.

Conclusion

The Bowstring Sign is a practical and efficient clinical test for assessing sciatic nerve irritation. While not diagnostic in isolation, it provides valuable information when combined with other neurological tests and clinical assessments. A positive finding indicates possible nerve root compression or irritation, and further imaging should be considered for a definitive diagnosis.

Sources:

1. Das JM, Nadi M. Lasegue Sign. StatPearls [Internet]. 2020 May 24.

2. Kamath, S. U., & Kamath, S. S. (2017). Lasègue's Sign. Journal of clinical and diagnostic research : JCDR, 11(5), RG01–RG02. https://doi.org/10.7860/JCDR/2017/24899.9794

3. Sports Injuries And Rehabilitation. Bowstring test. Available from:https://www.youtube.com/watch?v=dEX43YHaOxQ. [Lasted accessed: 26th Feb 2021]

4. Berthelot JM, Darrieutort-Laffite C, Arnolfo P, Glémarec J, Le Goff B, Maugars Y. Inadequacies of the Lasègue test, and how the Slump and Bowstring tests are useful for the diagnosis of sciatica. Joint bone spine. 2020 Jun 16:105030.