Traumatic diaphragm hernia can occur in rare cases and generally accompanies thoracic or abdominal injuries. When suffering from ankylosing spondylitis, a small force can develop into vertebral fracture and an adjacent structural injury, and lead to diaphragm hernia without accompanying concomitant thoracoabdominal injury. A high level of suspicion may be a most reliable diagnostic tool in the detection of a diaphragm injury, and we need to keep in mind a possibility in a patient with ankylosing spondylitis and a thoracolumbar fracture, even in the case of minor trauma.