Unilateral chest wall paradoxical motion mimicking a flail chest in a patient with hemilateral C7 spinal injury.

After a lower hemi-cervical spinal cord injury, a patient presented with a left hemiplegia and on the same side a unilateral chest wall paradoxical motion mimicking a flail chest. X-rays demonstrated a left hemilateral C6 injury but no rib fractures. We demonstrated that the paradoxical motion was due to the action of the diaphragm acting on the rib cage with intercostal respiratory paralysis on the side of hemiplegia.