Bowstring sign is also known as the popliteal compression test or posterior tibial nerve stretch sign. The patient can be examined in sitting or in a supine position. The examiner flexes the knee and applies pressure on the popliteal fossa, evoking sciatica. Some examiners do it after SLRT by flexing the knee to relieve the buttock pain. The pain would be reproduced by a quick snap on the posterior tibial nerve in the popliteal fossa.[rx]
Bowstring sign is a passive provocative clinical test that is performed in patients presenting with low back pain to determine the lumbosacral nerve tension. It is also known as the popliteal compression test or posterior tibial nerve stretch sign.[rx]
The patient begins lying supine with the legs extended while the examiner performs a passive straight leg raise on the involved side. If the patient reports radiating pain, the examiner then flexes the patient’s knee until symptoms are reduced. The examiner then applies pressure to the popliteal fossa to try to reproduce the radicular pain.
Patient in supine lying position without a pillow.
Examiner stands at the tested side with a face facing towards the patient’s face.
- Initially, the examiner performs the Straight Leg Raise ( SLR) test in which the examiner lifts the leg with the extended knee. Examiner raises the leg to the point where the patient perceives pain along with the distribution lumbosacral dermatomal level or when maximum flexion is got.
- While performing the SLR test, at the point of maximum pain (positive SLR) the examiner will slightly flex the patient’s knee approximately 20 degrees thereby reducing the pain.
- Then examiner applies pressure (via thumb) on the popliteal fossa on the sciatic nerve (posterior tibial nerve).
- If this elicits the same pain as the patient experiences during SLR, then the Bowstring sign is said to be positive.[rx]
- This test should be performed on both legs, the normal side being the first.
- The bowstring sign is one of the commonly used variants of the SLR test and a study published in 2020 suggests using SLRT, Femoral nerve tension test, Slump test, and bowstring test in combination. This takes about 2 minutes and could improve both the sensitivity and specificity of the physical examination for the diagnosis of sciatica.[rx]
- There is no evidence regarding the psychometric properties of the Bowstring sign.
Positive test Result
- Reproduction of pain with popliteal compression implies sciatic nerve pathology.