Abdominal trauma is probably the most difficult and most subjective type of trauma that you can evaluate. There is no perfect decision criteria that you can use. There is no perfect test. It all comes down to some magical combination of clinical gestalt and objective findings. Sure, we can usually tell when the patient needs to go straight to the OR, and we do have some great tools such as bedside ultrasound. However, none of these work 100% of the time. That is why I always consider three things when thinking through these cases. Mechanism, Exam, and Imaging.