The Bowstring sign is a clinical test used to assess nerve root irritation or compression in the lower back.
During the test, the patient is asked to lie on their back with their legs straight. The examiner then lifts one leg up by the ankle, keeping the knee straight, and applies pressure to the back of the patient's thigh. This pressure causes tension in the sciatic nerve, which runs down the back of the leg.
If the nerve is irritated or compressed, the pressure on the back of the thigh will cause pain in the lower back or down the leg. The Bowstring sign is considered positive if the pain is reproduced during the test.
The test is often used in conjunction with other tests to diagnose conditions such as sciatica, herniated discs, or spinal stenosis. It should be performed by a trained healthcare professional and interpreted in the context of the patient's symptoms and medical history.