A Multi-Scale Finite Element Model of Bruising in Soft Connective Tissues.

The failure of capillaries, or bruising, is a common physical exam finding following blunt trauma, and can be indicative of intentional trauma and abuse. However, despite the obvious clinical and forensic applications, there exist no computer models of bruising in soft connective tissues. We generated a finite element model of an adult female human arm segment, including skin, adipose, skeletal muscle, and bone, to determine the relationship between applied load, and the stresses and strains experienced by the tissue layers when impacted by a punch. The maximum principal stress in the wall of the capillary was 89.6 kPa, indicating that bruising would likely result in the skin, adipose, and skeletal muscle under these specific loading conditions, and that bruising is not limited to the impact site. The determination of bruise etiology has implications for forensic analyses and clinical procedures, and may have specific uses in characterizing abuse trauma.