Forensic medical cytological examination of the trace evidence on the knife’s blade in the case of multiple penetrating stab/cut wounds of the chest with a lung damage (a case from practice)

Abstract

Background. Various trace evidence are often found on the instruments of mechanical injury, and among them are microparticles of humans damaged organs and tissues. The detection of cells and microparticles of organs and tissues on the instrument of injury confirms the fact of its contact with the human body, which is of great evidentiary value. Case presentation. The article presents the results of forensic medical cytological examination of biological evidence taken from the knifes blade in the case of multiple penetrating stab/cut wounds of the chest with а lung damage. Microscopic preparations were prepared from the traces on knifes blade, which were stained with solutions of fluorochromes (0.0005 % aqueous solution of atebrine and 0.01 % solution of acridine orange). The study was performed using the luminescent microscope "LEICA DM 2500" (объективы 20х и 60х, окуляр 10х). Within the research the microparticles of striated skeletal muscle, areolar connective tissue and fat tissue with fragments of capillaries and arterioles were detected. The isolated mesothelial cells and type II pneumonocytes were also detected. The fibers of striated skeletal muscle tissue looked like long multinucleated cells with distinguishing cross-striation. Areolar connective tissue was represented by loosely arranged fibers which were embedded in the ground substance. The fragments of fat tissue looked like the "clusters" of round and oval large cells, tightly pressed together, with capillaries and arterioles between. Y-chromatin was detected in the nuclei of most cells. In addition, human blood was found on the knifes blade. Conclusion. Thus, as a result of the study, tiny particles of tissues and isolated human cells of the male genetic sex were detected, their organ-tissue affiliation was established, which is a valuable diagnostic find, since it confirms the fact of contact of the trauma instrument with the human body.