Expose and identify the spinal cord and its associated meninges.

1. The transversospinalis muscles fill the space between the transverse and spinous processes. (G 1.27;N 173;Gl 3.13A) Explore these muscles and their attachments. Attempt to identify the rotatores brevis and longus muscles.  Use a chisel to scrape these muscles from the vertebrae from the level of the iliac crest to the 8th thoracic spinous process (approximate).
   Important Relationship

   The erector spinae muscles are positioned superficial to the transversospinalis muscles.

2. Use an electric anatomy saw to sever the exposed spinous processes from the laminae.
3. Next make a series of angled (towards the midline) cuts through the laminae medial to the articular processes. Refer to a skeleton if you have difficulty visualizing these cuts.
4. Make two transverse cuts (superior at the level of T8 and inferior at the level of the iliac crest) between adjacent laminae and use a chisel to remove the posterior aspect of the vertebral column.
5. Identify and wipe off the exposed dura mater with a wet paper towel. (G 1.37;N 165;Gl 4.7)
6. Expose the spinal cord by using scissors to make a midline longitudinal incision in the dura.
7. Identify the arachnoid mater, spinal cord, dorsal and ventral roots (observe the dorsal and ventral roots in the cross section. Move through the cross sections 1 mm at a time and trace the dorsal and ventral roots to the dorsal root ganglion), conus medullaris, (follow the cross sections inferiorly in 1 mm steps to the tip of the conus medullaris) cauda equina (no structure is identified in the 3D Dissection Area as the cauda equina BUT the impression that the lumbar and sacral spinal nerve roots resemble a horse's tail is apparent in both the dissection and cross section areas) and filum terminale. (The filum terminale is not labeled as such. The spinal cord highlighted in slice 1651 may be the filum terminale. It will continue down to the sacrum. Observe the cross sections both superiorly into the conus medullaris and inferiorly from slice 1651 to follow the non-labeled filum terminale to the sacrum.) (G 1.38;N 165;Gl 4.9)
8. Attempt to identify a dorsal root ganglion and dorsal and ventral rami of a spinal nerve by chipping away the vertebral superior and inferior articular processes and any remaining lamina.