First and second year — the floor first, then every step
Name the morphology (compression, burst, distraction, translation), prove or disprove posterior ligamentous complex disruption, and measure height loss, kyphosis and canal compromise.
Orient first
A compression fracture fails the anterior column only; a burst fracture also fails the posterior wall of the body — retropulsion into the canal is what makes it a burst.
The posterior ligamentous complex (supraspinous and interspinous ligaments, ligamentum flavum, facet capsules) is the tension band; its disruption is what converts a stable-looking fracture into an unstable one.
Horizontal fractures through the posterior elements and body (Chance) mean the spine was distracted around a fulcrum — typically a lap belt — and travel with bowel and mesenteric injury.
Acquire the study
The trauma CT chest/abdomen/pelvis data set reconstructed as thin bone-algorithm slices of the spine with SAGITTAL and CORONAL reformats is usually sufficient; a dedicated spine CT is not needed if these exist.
Read bone AND soft-tissue windows — paraspinal haematoma on the soft-tissue window points to the injured level.
The manoeuvre
Sagittal midline reformat: count the levels from a reliable landmark (the last rib-bearing vertebra and the sacrum on the same study), then look at each body for height loss and posterior wall bowing or a retropulsed fragment.
Axial bone window at the injured level: posterior wall fragment, canal compromise, and the pedicles — widening of the interpedicular distance on coronal reformat means the posterior wall has failed.
Posterior elements on sagittal and axial: lamina and spinous process fractures, facet joint widening or perched facets, and splaying of the spinous processes (widened interspinous distance).
Horizontal fracture through the pedicles and spinous process on sagittal reformats — a Chance pattern.
Translation or rotation of one vertebra on the next in any plane — this is a translation injury, the most unstable type.
What confirms it
Burst: posterior wall involvement with retropulsion and/or widened interpedicular distance.
Posterior ligamentous complex disruption: widened interspinous distance, facet diastasis or perching on CT, or ligament discontinuity on MRI.
What licenses you to exclude it
CT cannot exclude an isolated ligamentous injury; if the mechanism and pain suggest it, say MRI is required to assess the posterior ligamentous complex.
The classic misread
Calling a burst fracture a compression fracture by not looking at the posterior wall on axial slices.
Mis-numbering the level — confirm the count on a coronal that shows the ribs and the lumbosacral junction; state the counting method.
Missing a second, non-contiguous fracture (up to a significant minority of spinal injuries) — read the whole spine.
Calling an old wedge compression acute: sclerotic endplates and osteophytes against marrow oedema on MRI.
Reporting the injury
Classification to use
AO Spine thoracolumbar classification: A (compression — A0–A4), B (tension band — B1–B3), C (translation), with neurology and modifiers; or TLICS (morphology + PLC integrity + neurology score). State which.
Measurements — and how to take them
Vertebral body height loss: anterior (or the most affected) height as a percentage of the expected height from the adjacent levels.
Segmental kyphosis: Cobb angle between the superior endplate of the vertebra above and the inferior endplate of the vertebra below, in degrees.
Canal compromise: residual AP canal diameter at the injured level relative to the mean of the levels above and below, as a percentage; retropulsed fragment depth in mm.
Interpedicular distance compared with the adjacent levels.
What to report
Level (with the counting method), morphology and every involved element.
Posterior wall involvement, retropulsion in mm, canal compromise percentage.
Posterior ligamentous complex: intact, indeterminate or disrupted, and on what evidence.
Non-contiguous fractures, paraspinal haematoma, and in a Chance pattern the bowel and mesentery.
How to report it
CT: "L1 burst fracture (AO Spine A4) with 40% loss of anterior body height, 8 mm retropulsion of the posterosuperior fragment and approximately 45% compromise of the canal. The interspinous distance at T12/L1 is not widened and the facets are congruent; posterior ligamentous complex intact on CT."
MRI: "High STIR signal and discontinuity of the T12/L1 interspinous and supraspinous ligaments — posterior ligamentous complex disruption."
What not to report
Do not grade a fracture "stable" without describing the posterior ligamentous complex.
Do not quote height loss without saying which part of the body (anterior, middle, posterior) was measured.
Associated injuries to look for
Chance (flexion-distraction) injury → bowel and mesenteric injury, pancreatic and duodenal injury.
Calcaneal fractures from a fall from height → look at the lumbar spine (and vice versa).
Rib, sternal and aortic injury with thoracic fractures.
What changes management
Posterior ligamentous complex disruption, a translation injury, or neurological deficit with canal compromise — surgical referral.
Progressive kyphosis on standing radiographs after bracing (a follow-up comparison against the supine CT).
Reference values
Each value carries the caveat that keeps it from being misused. Normal limits and diagnostic criteria are kept apart on purpose: a disease cut-off read as a normal range is the more dangerous mistake.
Normal limits
Spinal cord · Anteroposterior cord diameter, cervical and thoracic
the cord tapers from cervical enlargement to thoracic; compare with adjacent levels rather than quoting a single millimetre for the whole cord
A universal "normal cord is X mm" is wrong at most levels. Myelomalacia is volume LOSS plus T2 signal; swelling is the acute-injury / inflammatory pattern.
MRI
Thoracic spinal cord · Thoracic cord bulk relative to the cervical enlargement
the cord tapers below the cervical enlargement; a thoracic cord that is bulkier than the cervical cord is swollen until proven otherwise
Compare levels on the same sagittal. A "normal thoracic millimetre" copied from a cervical table is a wrong number.
MRI
Diagnostic criteria
Vertebral body · Vertebral height loss (Genant semiquantitative)no height loss
Lateral spine imaging. Anterior, middle and posterior vertebral heights compared with the adjacent normal vertebrae: grade 1 mild 20–25%, grade 2 moderate 25–40%, grade 3 severe above 40%.
⚠️ A HEIGHT LOSS IS NOT AUTOMATICALLY AN OSTEOPOROTIC FRACTURE — Scheuermann change, Schmorl nodes, congenital variants and malignant infiltration all reduce height, and marrow signal on MRI is what separates acute from chronic and benign from malignant.
X-ray · CT · MRI
See it on real cases
Direct links to Radiopaedia — the reference article and worked cases with their images. Each opens on Radiopaedia.