Straight Leg Raising Test is one of the most common neurological tests of the lower limb. It is a passive test, and each leg is tested individually with the normal leg being tested first.
The SLR test is recognized as the first neural tissue tension test to appear in the medical literature. It was first described by Lasègue well over 100 years ago.
With the patient in the supine position, the hip medially rotated and adducted and the knee extended, the examiner flexes the hip until the patient complains of pain or tightness in the back or back of the leg.
If the pain is primarily back pain, it is more likely a disc herniation from pressure on the anterior theca of the spinal cord or the pathology causing the pressure is more central.
The patients with only Back pain are those who have a disc prolapse have smaller, more central prolapses.
If pain is primarily in the leg, it is more likely that the pathology causing the pressure on neurological tissues is more lateral.
The evaluation of the findings from the SLR test requires that the range of motion measured and the symptoms produced are compared with the contralateral side and with expected norms.
Pain in the 0 to 30 degree range may indicate the presence of :
Between 30 and 70 degrees, the spinal nerves, their dural sleeves, and the roots o the L4, L5, S1, and S2 segments are stretched with an excursion of 2–6 mm.
After 70 degrees, although these structures undergo further tension, other structures also become involved. These additional structures include the hamstrings, gluteus maximus, hip, lumbar, and sacroiliac joints.
An SLR test is positive if :
the range is limited by spasm to less than 70 degrees, suggesting compression or irritation of the nerve roots.
A positive test reproduces the symptoms of sciatica, with pain that radiates below the knee, not merely back or hamstring pain. When the SLR is severely limited, it is considered diagnostic or a disk herniation.
The pain reproduced is neurologic in nature. This pain should be accompanied by other signs and symptoms such as pain with coughing, tying shoe laces, and so on but not necessarily by muscle weakness.
Braggard’s test :Passive dorsiflexion of the ankle is added with the SLR test.
Soto-Hall test : Along with above passive cervical flexion may be used as sensitizers or the SLR test.