Forensic anthropologists have become increasingly involved in the interpretation of skeletal trauma caused by exploding ordnance. This study examines the cause and significance of butterfly fractures observed in a recent study investigating skeletal blast trauma by Christensen et al. Fractured ribs resulting from blast events carried out in the original study were re-examined revealing that rib butterfly fractures with the tensile indicator on the visceral surface were present in 100 percent of viable pig specimens. Additionally, manual fracture testing was performed on 46 pig ribs to simulate the bending force believed to have been sustained in the original blast events. Fracture testing resulted in 93 percent of specimens presenting butterfly fractures with the tensile indicator on the visceral surface. This fracture pattern differs significantly from that normally observed in association with other types of trauma events and may aid forensic anthropologists and other investigators in the identification and interpretation of blast events. Abstract published by arrangement with John Wiley & Sons.