外科急诊创伤英文贯通伤.pptx

外科急诊创伤英文贯通伤第1页/共40页 Penetrating Trauma第2页/共40页 Sections Introduction to Penetrating TraumaPhysics of Penetrating TraumaSpecific Tissue/Organ InjuriesSpecial Concerns with Penetrating Trauma第3页/共40页 38,000 Deaths in US annually due to shootings.Mechanisms of penetrating traumaKnives, Arrows, Nails, etcUnderstanding principles of energy exchange increase the Index of Suspicion associated with the MOIIntroduction to Penetrating Trauma第4页/共40页 Recall Kinetic Energy EquationGreater the mass the greater the energyDouble mass = double KEGreater the speed the greater the energyDouble speed = 4x increase KEPhysics of Penetrating Trauma(continued)第5页/共40页 第6页/共40页 Physics of Penetrating TraumaSmall Fast bullet can cause greater damage than large and slow.Different bullets of different weights traveling at different speeds causeLow Energy/Low VelocityKnives and arrowsMedium Energy/Medium Velocity WeaponsHandguns, shotguns, low-powered rifles250-400 mpsHigh Energy/High VelocityAssault Rifles600-1,000 mps(continued)第7页/共40页 Physics of Penetrating TraumaBullet spins as it travels down barrelRifling in barrelAllows bullet to travel straight with slight yawBullet departs barrel, spinning with a slight wobble or yawWeapon forced backward and absorbs energyRecoil(continued)第8页/共40页 Physics of Penetrating TraumaRemainder of energy propels bullet forward at a high rate of speed.Trajectory is curved due to gravityAs bullet strikes object, it slows and energy is transferred to object.Law of Conservation of Energy第9页/共40页 BallisticsStudy of the characteristics of projectiles in motion and effects upon objects impactedFactors affecting energy exchange between a projectile and body tissueVelocityProfileStabilityExpansion FragmentationSecondary ImpactsShape第10页/共40页 Energy DissipationDrag: wind resistanceCavitation: formation of a partial vacuum and cavity within a semi-fluid mediumProfile: Size and shape of a projectile as it contacts a targetLarger the profile=greater energy e