abstract:For the FNST the patient lies prone, the knee is passively flexed to the thigh and the hip is passively extended; the test is positive if the patient experiences anterior thigh pain. This test is usually strongly positive in patients with protrusions at L2-L3 and L3-L4, slightly positive or negative in L4-L5 disk protrusions and negative in cases with a lumbosacral protrusion.