Fig. 2. These images depict the desired ultrasound image and probe position for evaluation of the lumbosacral joint, including the LS disc, in a median plane (A1 and A2) and a transverse plane (B1 and B2). This represents Step 1 of the examination. Stars mark the spinal cord; X marks the ventral longitudinal ligament.
the defect is identified, look for the L6 nerve root that can be identified as a bundle of long, parallel, hyperechoic fibers. When the foramen is first iden-
tified, the imaging plane will be oblique to the nerve, and probe manipulation is needed to orient the ul- trasound probe parallel to the nerve root to char-
Fig. 3. This image depicts a paramedian plane of the lumbosacral intertransverse joint and the associated probe position along the ventral aspect of the sacrum. This represents Step 4 of the examination. Arrow demarcates the joint space.
