A traumatic infra-renal aortic dissection is a rare but life-threatening injury that follows deceleration injuries. The mechanism of blunt abdominal aortic injury involves both direct and indirect forces. The successful management of patients with traumatic injuries depends on a prompt suspicion of the injury and early diagnosis and therapy. Missed injuries in trauma patients are well-described phenomena and implementation of the ATLS® trauma schedule led to a decrease in the number of missed injuries, but trauma computed tomography (CT) scans in injured patients are still not standard. We report on a 54-year old Caucasian female patient who was involved in a car accident. The fellow passenger of the car was seriously injured. The patient had been previously treated at two different hospitals, and a dislocated acetabular fracture had been diagnosed. Because of this injury, the patient was transferred to our institution, a level 1 trauma-center where, according to the nature of the accident as a high-energy trauma, a complete polytrauma management was performed at the time of admission. During the body check, a moderate tension of the lower parts of the abdomen was detected. During the CT scan, an aneurysm of the infra-renal aorta with a dissection from the height of the second lumbar vertebral body to the iliac artery was observed. The patient required an operation on the day of admission. After 19 days post-trauma care the patient was able to leave our hospital in good general condition. Therefore, missed injuries in multiple injury patients could be fatal, and it is essential that the orthopedic surgeon leaves room for suspicion of injuries based on the nature of the trauma. Traumatic injuries of the abdominal aorta are rare. According to the ATLS® trauma schedule, all of the patients who have experienced high-energy trauma and associated fractures should undergo routine screening using a trauma CT scan with contrast agents to detect potential life-threatening injuries. In case of abdominal trauma, an aortic dissection, which can easily be overlooked, has to be considered.