Hey guys here's another clinical sign!
Lasegue’s sign is another name for the modified straight leg maneuver used in the diagnosis of lumbosacral radiculopathy.
To perform the straight leg test, the clinician lifts the extended leg of a patient in a supine position. A positive response occurs when the pain pattern of the lumbar radiculopathy is reproduced. The test should be stopped when the pain is reproduced or maximum flexion is achieved.
But this sign is difficult to evaluate clinically especially for students. The reason being as simple as that it has been performed many a times before and patient already knows that he is going to suffer pain. So it was modified a bit by Lasague, he proposed that the leg should be raised while the knee is flexed by flexing the thigh at the hip joint. And then the knee is slowly extended until the patient complains of pain. In severe cases patient will complain of pain even during the flexion of hip.
More useful than the straight leg maneuver is the crossed straight leg test. This test has a lower sensitivity but a higher specificity. The crossed straight leg maneuver is performed by raising the unaffected leg in a similar manner to the straight leg test. The examiner looks for the reproduction of radicular pain with elevation of the opposite leg.
A supplement to this straight leg raising test is Braggard's test. First we have to start raising the leg of the patient while his knee is extended until he complains of pain and then dorsiflex his foot, if the pain worsens, it's a positive Braggard's test.
But as given in most books, these signs are not only positive in case of lower lumbar vertebral disc lesions but also in a no of other conditions. The differential diagnosis of a positive straight leg test includes:
1. disc protrusion with impingement of nerve roots below L4;
3. any intraspinal lesion such as tumor below L4;
4. malignant disease or
5. osteomyelitis of the ilium or upper femur;
6. ankylosing spondylitis;
7. fractured sacrum and more.