Positive straight leg raising test secondary to conjoined lumbosacral nerve roots

A 53-year-old man presented with low backache and left lower limb pain of 3 months' duration, without radicular pain or lower limb weakness. Straight leg raising test was positive but the remainder of the neurologic examination was normal. His lumbosacral spine MRI revealed left L4 and L5 conjoined nerve roots (figure, A.a-D.a). The imaging was positive for sagittal shoulder sign (figure, A.a) and axial image parallel sign (figure, A.b), both favoring conjoined nerve roots.(1) The absence of other neurologic signs with no imaging evidence of nerve root compression on the left suggests that the positive straight leg raising test was attributable to conjoined lumbosacral nerve roots.(2</SUP)