Chapter 7 Physical Trauma © 2012 Cengage Learning. All Rights Reserved

Introduction Physical trauma—any serious or life- threatening physical injury, wound, or shock Forensic Science II: Physical Trauma, Chapter 7 © 2012 Cengage Learning. All Rights Reserved 2

Evidence of Physical Trauma (Obj 7.1) The extent of the physical trauma depends on – the amount of force applied to the body, – the part of the body affected, – how much of the body’s surface was affected, and – the type of weapon used Forensic Science II: Physical Trauma, Chapter 7 © 2012 Cengage Learning. All Rights Reserved 3

Force is equal to mass times acceleration. The more massive the weapon, the greater the force exerted on the body. The more the weapon is accelerating upon impact, the greater the force exerted on the body. Forensic Science II: Physical Trauma, Chapter 7 © 2012 Cengage Learning. All Rights Reserved 4

Force Force = mass x acceleration Force is a push or pull applied to an object Forensic Science II: Physical Trauma, Chapter 7 © 2012 Cengage Learning. All Rights Reserved 5

Surface Area and Pressure Pressure = force / surface area Pressure is the amount of force per unit area A weapon with a larger surface area will inflict a less severe injury – High-heeled shoe – Ping Pong paddle Forensic Science II: Physical Trauma, Chapter 7 © 2012 Cengage Learning. All Rights Reserved 6

Types of Trauma Injuries to the body are usually classified as either blunt-force or sharp-force trauma. This classification is based on the type of wound produced and the weapon used. Forensic Science II: Physical Trauma, Chapter 7 © 2012 Cengage Learning. All Rights Reserved 7

Blunt-Force Trauma (Obj 7.2) Caused when a victim: hits or is hit by a hard object falls or is pushed into a hard Forensic Science II: Physical Trauma, Chapter 7 © 2012 Cengage Learning. All Rights Reserved 8 Types of Blunt force traumas Abrasions Contusions Lacerations

Forensic Science II: Physical Trauma, Chapter 7 © 2012 Cengage Learning. All Rights Reserved 9 Massive abdominal blunt force injury often leads to liver injury, since it is the largest internal organ. Note the multiple lacerations over the capsule. Damage to abdominal organs with lacerations, crush injuries, and rupture can lead to bleeding into the peritoneal cavity known as hemoperitoneum. A peritoneal lavage can detect such bleeding.