The Experimental Study Of Arterial Bloodstain In Dynamics And Morphology

Found evidence of the crime scene is of great significance for investigating this case, morphological evidence for investigating this case to provide strong clues in recent years more and more attention in the various countries of the world of forensic science field of criminal identification. Arterial bloodstain studies already have the attention of the experts and scholars at home and abroad, but the domestic jet bloodstains dynamics research has been blank. From a second crime occurred, specializes in bloodstain has become a golden key to reveal the truth of the crime. Arterial bloodstain come from the trauma caused by human arteries rupture, the formation of open wounds, the outflow of blood from the blood vessels. Due to heart beat, blood flow in the veins with a certain pressure. Blood leaving the body was spewing like and the spewing like blood left in the object to form arterial bloodstain. Arterial bloodstain is the most common bloodstain in crime scene. We know that the study of the hemodynamic direction from the static morphology can really find the real side of the form, and provide the most effective support and assistance for investigating the case. This study is focused on this breakthrough.Objective:Show the dynamic phenomena of the arterial bloodstain repeatedly by a variety of conditions and careful field simulation experiments, and quantify the dynamics indicators, so that we can digitized crime scene arterial bloodstain in investigating this case in the future, reveals its own rules, play focused on the vital role of crime scene reconstruction, lay the material foundation for investigating this case. Investigate the effects of pressure and diameter of vessel on the spraying distance and shape of arterial bloodstain.Methods:Established an indoor environment of the scene, and then simulate the human blood pressure by the pressure pump. Normal the human blood pressure as: systolic blood pressure90—140mmHg and diastolic blood pressure60—80mmHg. Taking into account the injury is a stress state or debilitating condition, blood pressure varying degrees of increase or decrease. Therefore, we have the experiments within the range of60-210mmHg sub-6pressure levels the blood injection under different pressures. Literature told us that in normal adult the internal diameter of artery are: carotid6.0-7.0mm, brachial artery3.0-4.3mm, ulnar artery1.5-3.4mm, radial artery1.7-2.9mm. Therefore, this experiment select four diameter1.5mm,2.0mm,3.5mm,4.5mm respectively analog wrist, forearm upper arm, shoulder and neck at the rupture of an artery. In different diameters conditions, production artery splashing blood on the model. Fresh pig’s blood as substitute of splashing with human’s blood, observing horizontal surface50cm,100cm,150cm three height analog leg, abdomen, chest and neck injuries arterial bloodstain on the distribution of blood on the size and morphological characteristics, measuring its distance, and analyzing them with SPSS13.0statistical software.Results:Both pressure and diameter have effects on the spraying distance and pattern in different spraying height and the two factors have interactive effects on the change of the spraying distance. Meanwhile there is a good linear relationship existing between the spraying distance and pressure and diameter, and it can leads to regression equation. The splashing blood morphology exhibits different characteristics in different spray height, pressure and diameter. These characteristics are mainly reflected in the size of the round droplets blood, oval drop-like conditions and size of the bloodstain appears, the edge of the satellite strains protrusions and around the satellite strains blood on the number and morphology. The overall trend: the greater the height higher the blood drop diameter; diameter of the thicker edge burr-like protrusions, the more obvious the more satellite-like blood; greater the pressure, the jet farther away from the edge of the drop of blood burr-like protrusions along the direction of the jet more and more, and gradually increased from the satellite-like blood, more elongated tailing; oval drop of blood pressure with an increase in diameter, the higher the same height of the ejection.Conclusion:It can be used to estimate the source of arterial bloodstain pattern and body posture when injured by observing and measuring arterial bloodstain and the spraying distance. Form of arterial bloodstain splash and spray distance observation and measurement can be used to infer the crime scene splash source location and infer the bleeding vessel diameter, thereby infer the parts of the body injured. Through a dynamic combination of the source of bleeding, the reproduction bleeding, so as to achieve the purpose of the scene reconstruction; scene reconstruction, clear the number of perpetrators, victims of tool types, victims process, motive. This study will provide strong academic support for the crime scene investigation. The experimental study of arterial bloodstain in dynamics and morphology used in the actual conduct of a case will increase the efficiency of crime case, and provide conclusive evidence for the prosecution of the case. But this article only blood on white paper formed under conditions of blood ejected in the horizontal direction and a preliminary observation, very much blood on the factors affecting the formation, the need to verify the use of regression equation also need to be tested. The remains are needed to be confirmed by further research.