A growing number of common traumatic events involve both physical and emotional injuries. In contrast to previously held beliefs, the rapidly growing body of literature shows quite convincingly that physical injury, over and above exposure to the traumatic event itself, increases rather than decreases the risk for posttraumatic stress disorder (PTSD). A pertinent question becomes how bodily injury contributes to the risk of developing PTSD. In this article, we review contemporary findings regarding the neurobiological and psychological mechanisms by which bodily injury may augment or independently contribute to chronic posttraumatic stress. In addition, we propose three theoretical pathways through which physical injury can increase the risk for PTSD. These pathways are: additive, unique, and recovery impeding. Finally, we highlight unresolved issues pertaining to each one of these pathways and propose directions for future research to address them.