This article is designed to review all the basics around spine anatomy that would be helpful for performing procedures. Any pain management inverventionalist/proceduralist will rely on this basic anatomy and understanding of fluoroscopy images and C-arm use. It is written with a few basic goals:
- Review basic vertebrae and spine anatomy
- Discuss that in the context of fluoroscopic images and C-Arm positioning for procedures
- Outline basic principles that can set a foundation for the various articles on this site
There are generally 5 lumbar vertebrae. Most procedures revolve around knowing the basic structures of the vertebrae in the diagram and are referenced throughout this site:
- Transverse process (TP)
- Spinous process (SP)
- Superior articulating process (SAP)
- Inferior articulating process (IAP)
- Neuroforamen (NF)
There are generally 3 common views utilized under fluoro. The exact alignment of the c-arm will vary with each level and person. These basic steps help acquire a good enough image for a procedure:
AP (Anterior-Posterior) fluoroscopy view
- The spinous processes should be midline.
- Flatten the endplates at the level that you’re working on.
- With significant scoliosis you can’t get all SPs midline, so you do so at the levels you’re interested in.
Lateral fluoroscopy view
Oblique/scotty dog fluoroscopy view
- Attempt to look down the barrel of the facet joint at the level you’re working at. This means you see the facet joint straight on so it is lucent/transparent
- Scotty dog (highlighted here in green)
- Nose = TP, ear = SAP, front foot = IAP, body = lamina
EXAMPLE 1: You want to place a needle at the junction of the TP and SAP at L4 on the left (also known as a left lumbar medial branch block at L4).
Cervical imaging can be tricky:
- Most work (medial branch blocks, epidurals, radiofrequency ablations) is done in the lateral or oblique view (as opposed to an AP view, which is more important for lumbar/thoracic work)
- If you can obtain good imaging, the procedures will be much smoother:
- Many factors effect images such as patient size, body habitus, and positioning.
- Try to position the patient so the neck is in a “long”, neutral position. A twisted neck can make lateral and AP views misaligned.
- Avoid flexion, except CESIs where you want the head flexed on the neck.
- Hunched shoulders can obscure the lower levels of the neck in a lateral view.
- Try to have the shoulders pulled down slightly and/or curled forward to get them out of the way.
- Obese patients often have fat that limits access to the injection site or obscures the image.
- If the patient is in a prone position you can tape back pannus: apply tape near the neck and pull down a long strip towards the low back. This pulls down some of the pannus out of the way.
- Hair can get in the way
- Have patients wear a bouffant with hair tied inside. All of this can be taped up after positioning.
- LATERAL VIEW
- Line up the borders of the lateral mass/articulating column so you don’t see “double images” when the left and right are out of alignment.
- C-Arm POSITIONING
- After obtaining a good lateral view simply rotate the c-arm in one axis to get the AP view. This minimizes motion of the c-arm and wasted time re-establishing images.
Naming/Numbering of bony structures and nerve roots