Post-traumatic headache (PTH) is a common and disabling symptom secondary to the traumatic event. It is known that assault is associated with a wide range of physical symptoms including PTH. In this work, the general causation approach provided by the Hill criteria is described as an assessment tool for specific causation with regards to PTH and sexual assault. Time-dependent models of probability and, in-turn, relative risk are described as quantitative algorithms for addressing inductive and abductive conclusions of causation in forensic science.