Imaging the Lumob-Sacral Plexus

The lumbo-sacral plexus is the region of the caudal spine where the peripheral nerves branch off of the spinal cord and extend into the hind limbs. Imaging of this area should include a larger field of view and enough slices to cover the entire region. The plexus covers and area from L4 to S3 and extends laterally through the hips. The majority of the primary branches of the plexus only extend out as far as the lateral margins of the pelvis. It is best to start with a large Coronal STIR or T2 fat saturated sequence that covers all of the anatomy to help narrow down the focus for the rest of the study. Additional imaging of the plexus may include a "Double Oblique" T2 weighted sequence in order to acquire a true cross section of the sciatic nerve. As you can see in the image below the sagittal slice group is angled parallel to the wing of the pelvis on the side of interest in the coronal plane. Then the slice group is also adjusted in an oblique angle in the axial plane parallel to the posterior margin of the wing.