In a patient in the supine position, raising the leg with the knee extended stretches the nerve root over the protruded disk and results in a response of muscle contraction. A positive test consists of reproduction or marked Worsening of the patient’s initial pain and firm resistance to further elevation of the leg. A diagnosis of disk compression is likely if pain radiates from the buttock to below the knee when the angle of the leg is between 30 and 70 degrees. Many persons without spinal abnormalities have hamstring and gluteal tightness With discomfort elicited by straight leg raising, but the pain is more diffuse than in sciatica and the leg can be lifted higher if the maneuver is performed slowly. Increased pain on dorsiflexion of the foot or large toe increases sensitivity. The crossed straight-leg-raising test (Fajersztajn’s test) involves raising the unaffected leg; in a positive test, sciatic pain is elicited in the opposite (affected) leg. This test is 90% specific for disk herniation on the contralateral side but is insensitive. 
#Diagnosis #PhysicalExam #StraightLeg #Lasegues #Test #Sciatica