Read our step-by-step guide to interpreting thoracic and lumbar spine x-rays.
Thoracolumbar spine x-ray involves two views – AP and lateral.
Check it’s an adequate view
For a lumbar spine view
- you should be able to see L1-L5 but also the full T12 vertebral body, T11/12, and the sacrum on the AP view
- the vertebral bodies, facet joints, and pedicles should be clearly visible on the lateral view
- the transverse processes should also be visible (and are often obscured by gas)
For the thoracic spine view
- make sure the whole thoracic spine is visible
- you should be able to see the pedicles, spinous processes, and vertebral bodies
- the ribs can cause difficulty seeing the thoracic spine on a lateral view
2. Know your anatomy
- Clavicle is at T3
- Tracheal bifurcation is T4/5
- 12th rib is at T12
- In the lumbar spine, the disc spaces also increase in size, although note that the L5/sacral space is narrower than the L4/L5 space
3. Check the alignment
On the AP check that the vertebral bodies and spinous processes are aligned. On the lateral, check the alignment of the vertebral bodies.
4. Look for loss of vertebral height
In the thoracic spine, the vertebral bodies (and the disc spaces) should gradually increase in size as you get further down the spine.
Check all the vertebral bodies looking specifically for loss of height. This indicates a compression fracture.
5. Look for widened inter-spinous or inter-pedicle distance and check the processes
In the lumbar spine check that all the pedicles, spinal, and transverse processes are intact.
See below (under burst fracture) for an example of widened inter-pedicle distance and (under Chance fracture) widened spinous process process distance.
6. Check for translation/rotation or distraction
Translation or rotation is displacement in horizontal plane; and distraction is displacement in the vertical plane.
Translation/rotation is due to a side-to-side motion (can be left-to-right or front-to-back). It is a serious injury and always involves the posterior ligamentous complex.
Distraction is where the vertebrae are pulled apart and carries a high risk of cord injury. Often there is compression at the other side (see Chance fracture below).
7. Know the common types of fractures
This is the most common type of fracture and is identified through loss of vertebral height (see number 4 above). It involves one column only and is a stable fracture.
On x-ray alone 25% of burst fractures are misdiagnosed as vertebral compression fractures. A burst fracture is where there is a compression, but part of the vertebral body has been projected out anteriorly.
On AP view there will be an increased interpedicular distance in 80% of burst fractures.
On lateral view there will be reduced vertebral height and disrupted anterior alignment.
Usually from a seatbelts injury and is commonly at L2/L3
This is a flexion-distraction injury where there is horizontal splitting of the vertebral body with ligament rupture. This is an unstable fracture and involves all three columns
Sometimes there is increased distance between the spinous processed on the lateral view (but not always).
On the AP view there can be increased distance between the spinous processes at the level of the Chance fracture.
So-called because it’s usually from people jumping out of windows to escape the police or angry partners. This is severe axial loading leading to compression/burst fractures alongside a calcaneus fracture.