Myelography involves injecting contrast media into which area?

• A. Subarachnoid space
• B. Spinal cord/Epidural space
• C. Lumbar intervertebral disc
• D. Cerebrospinal fluid

Answer: (B)

The key idea is that myelography visualizes the spinal cord and nerve roots by placing contrast where the cord sits. The contrast is injected into the subarachnoid space, the thecal sac that contains cerebrospinal fluid. By delivering contrast intrathecally, it mixes with CSF and outlines the spinal canal and nerve roots on imaging, making it possible to see compressions, herniations, or other abnormalities. Injecting into the epidural space wouldn’t fill the thecal sac with contrast, so you wouldn’t get the same detailed view of the spinal canal. The lumbar intervertebral disc is not a space used for this purpose, and while CSF is involved, the procedure targets the subarachnoid space, not merely the fluid itself.