Question:medium
A man met with an RTA and came to the emergency department with complaint of back pain. No neurological deficit. X-ray spine done — what will be the diagnosis?
A man met with an RTA and came to the emergency department with complaint of back pain. No neurological deficit. X-ray spine done — what will be the diagnosis?
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Seat-belt + flexion-distraction over a lap belt produces a horizontal fracture across the whole vertebra — think of the eponymous “seat-belt fracture.”
Updated On: Jun 22, 2026
- Fracture of spinous process
- Compressed fracture
- Fracture of base of vertebra
- Chance fracture
Show Solution
The Correct Option is D
Solution and Explanation
Mechanism-first reasoning.
Start from the energy involved. An RTA in a belted passenger generates a flexion-distraction force: the lap belt anchors the pelvis while the trunk jack-knifes forward. The axis of bending lies anterior to the spine, so the whole vertebra is pulled apart from back to front.
Translate the force into a fracture line. When a vertebra is distracted in this way, the failure runs horizontally through all three columns - spinous process, pedicles and body - in a single transverse plane. That injury has a name: the Chance fracture (the "seat-belt fracture"), most often at the thoraco-lumbar junction.
Check the clinical clues. The patient has only back pain with $no$ neurological deficit. A Chance fracture is often a bony, ligament-sparing injury that can be neurologically intact, so this fits.
Eliminate the rest:
• Spinous-process fracture = an isolated tip avulsion, not a transverse body split.
• Compression/wedge fracture = pure axial-load anterior collapse, posterior elements intact - wrong mechanism.
• "Fracture of base of vertebra" is not a defined seat-belt pattern.
Answer: the horizontal seat-belt distraction injury is a Chance fracture (Option D).
Start from the energy involved. An RTA in a belted passenger generates a flexion-distraction force: the lap belt anchors the pelvis while the trunk jack-knifes forward. The axis of bending lies anterior to the spine, so the whole vertebra is pulled apart from back to front.
Translate the force into a fracture line. When a vertebra is distracted in this way, the failure runs horizontally through all three columns - spinous process, pedicles and body - in a single transverse plane. That injury has a name: the Chance fracture (the "seat-belt fracture"), most often at the thoraco-lumbar junction.
Check the clinical clues. The patient has only back pain with $no$ neurological deficit. A Chance fracture is often a bony, ligament-sparing injury that can be neurologically intact, so this fits.
Eliminate the rest:
• Spinous-process fracture = an isolated tip avulsion, not a transverse body split.
• Compression/wedge fracture = pure axial-load anterior collapse, posterior elements intact - wrong mechanism.
• "Fracture of base of vertebra" is not a defined seat-belt pattern.
Answer: the horizontal seat-belt distraction injury is a Chance fracture (Option D).
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