Zygoma fracture as a result of baseball impact presents a particular concern due to its prevalence and importance as a structure of the orbit. The purpose of this study was to develop risk functions for zygoma fracture based on ball type and velocity. A normal distribution was assumed for previous data on the fracture strength of the zygoma. The fracture strength data was mapped with the force exerted by a baseball as a function of velocity to develop the zygoma fracture risk functions. The risk functions showed that a major league ball has a 50% chance of causing fracture at a speed of 31 mph. Experimental evaluation of the risk functions was performed using six cadaver tests and two baseballs of different stiffness values. Tests with a softer baseball did result in injury, however they occurred at velocities 50% higher than the major league ball with fewer resulting bone fragments. The experimental results validated the risk functions at the lower and upper level. Post test analysis of the skull was performed using CT imaging including 3D reconstruction as well as autopsy. The injuries observed in the post test analysis included fractures of the zygomatic arch, frontal process and the maxilla, zygoma suture, with combinations of these creating comminuted, tripod fractures of the zygoma.