Cranial blunt force trauma in relation to the victim's position: An experimental study using polyurethane bone spheres

Blunt force trauma is the most common injury found during autopsies. Among the cases involving blunt force injuries, fractures to the skull are the most frequent, and these are often fatal to the victim. Understanding the circumstances surrounding the creation of such injuries is essential for investigating trauma-related deaths. This paper explores the characteristics of cranial trauma produced following one to three consecutive blows with a series of blunt objects. Fourteen Synbone^® spheres filled with porcine gelatine and coated with rubber skin were used to simulate the human skull in a series of experiments. Trials recreated two scenarios, individuals standing and individuals with their head resting against a hard surface. Six blunt objects were used to represent possible weapons. Each sphere was struck twice to generate fracture patterns, which were then analysed. In most simulations of a blow to the head resting against a hard surface, the first fracture follows a linear pattern regardless of the direction of force and/or the surface of the weapon; while the second blow results in a depressed fracture. In the case of a free moving head, weapons with large contact surfaces result in depressed fractures, while weapons with small contact surfaces may not cause a fracture at all. Our results are consistent with Moritz who stated that, if the head is free to move, the fractures will be linear or incompletely depressed. Inversely, if the head rests against a solid surface, a blow will result in a depressed fracture. More experiments are needed to verify these preliminary observations.