Asphyxiating Thoracic Dystrophy Etiology: congenitalImaging: short ribs, bowed extremities, trident pelvis, normal spineClinical: lethal skeletal dysplasia Radiology Cases of Asphyxiating Thoracic Dystrophy CXR AP shows shortened ribs resulting in a small thorax and a normal spine. Gross Pathology Cases of Asphyxiating Thoracic Dystrophy Post-mortem gross pathological image shows an extremely small thorax due to shortened ribs, particularly when compared to the size of the abdomen.