[Study of morphometric parameters of the hyoid bone]. / Issledovanie morfometricheskikh priznakov pod"yazychnoi kosti.

THE OBJECTIVE OF THE WORK: Is to study the morphological and morphometric variations of the hyoid bone in the population of the Tver region. One hundred adult hyoid bone samples were taken from 63 males and 37 females. Morphological and morphometric variations of the hyoid bone were determined. Six types of hyoid bone were identified: U-shaped - 25 bones (25%); H-shaped - 3 bones (3%); B-shaped - 48 bones (48%); D-shaped - 14 bones (14%); V-shaped - 2 bones (2%); HK-shaped - 8 bones (8%). The width, length, and the largest transverse axis were 42.44; 36.49, and 35.6 mm, respectively. Morphological differences of the hyoid bones of the Tver region population compared to other populations were found. Anatomical variations and dimensions of the hyoid bone are important for practical forensic medicine.

[General characteristics of morphometric and morphoscopic signs of liver rupture with different localizations]. / Obshchaia kharakteristika morfometricheskikh i morfoskopicheskikh priznakov razryvov pecheni razlichnoi lokalizatsii.

The aim of this study was to compare the morphoscopic and morphometric features of local and remote liver ruptures under various external influences. It was found that the local main ruptures were formed in the case of impact trauma more often in the right side of the liver on its diaphragmatic surface, in the anterior third of the organ. They were linear and located in the longitudinal direction. The size of the ruptures increased as the impact force increased. Local additional ruptures were associated with impact and compression trauma and were located only on the diaphragmatic surface of the liver, more often in the right half, in the middle third of the organ. These ruptures were linear, co-directional and small in size under various external influences. Central ruptures were formed by impact and compression trauma, were located more often in the middle third of the right side of the liver and were slit-shaped with a longitudinal direction. The size of central ruptures was associated with falls on the stomach and compression trauma. Peripheral ruptures were formed in the case of impact and compression trauma, were located more often in the right half of the liver on its diaphragmatic surface, mainly in the middle third of the organ and were linear with a slanting direction. The relative constancy of the average sizes of peripheral ruptures was noted. Anti-shock ruptures were observed resulting from shock trauma and were located more often in the right side of the liver, on its visceral surface, in the rear third of the organ. They were linear and curvilinear, and longitudinally and obliquely oriented. Ruptures were relatively constant in size with different types of impact.

[The peculiar morphological features of the surface relief of the major local ruptures of the liver in the case of a blunt injury]. / Morfologicheskie osobennosti rel'efa poverkhnosti mestnykh osnovnykh razryvov pecheni pri tupoi travme.

The objective of the present study was the comprehensive investigation of morphogenesis of the surface relief of the major local ruptures of the liver in the case of a blunt injury and the obtaining of an additional information on the possibility to use these data for the purposes of forensic medical expertise. We explored the reliefs of the major local ruptures of the liver in the cases of a single fatal blunt injury inflicted in a traffic accident, by kicking or a powerful stroke with the fist. In addition, the threshold hepatic lesions depending on their severity were determined experimentally. The model allowing to describe the qualitative relief alterations of the rupture surface associated with a blunt injury has been developed. The main elements of the surface relief of the major ruptures include avulsion and shear ridges, folds as well as 'extension zones'. Three types of possible rupture surface reliefs have been identified, viz. relatively uniform, stratified and fragmented non-uniform ones. Such reliefs are formed in the case of a threshold injury, powerful stroke with the leg or the fist, and road traffic accident, respectively. The location of the shear ridges at the ruptured surface makes it possible to determine the direction of growth of the local major rupture and of the stroke vector. The presence of multiple 'extension zones' at the surface of the local major rupture may serve as an indicator either of the influence of the unlimited traumatic surface or of the very strong stroke. The above features of the relief of the rupture surface provide the conditions for the application of the statistical approach to the elucidation of the mechanisms underlying the deformation and the destruction of the parenchymatous organs suffering a blunt injury.

[Current concepts of the mechanisms of formation of gunshot fractures].

The mechanisms of formation of gunshot fractures in flat bones inflicted by a semispherical bullet were investigated using expert and experimental materials. The process of crack formation was considered in terms of the Hertzian contact problem and the Hill-Johnson model. It was shown that the fracture develops as a result of combination of stresses and strains in the bone tissue leading to the formation of a hydrostatic nucleus prior to tissue fragmentation. Dynamic fluctuations (waves) generated in the zone of hydrostatic compression resulting from the gunshot injury propagate with the velocity of sound from the nucleus in the direction of the bullet movement. According to the Hill-Johnson model, the waves propagate in the direction of the impact within a parabolically expanding space; this accounts for the mechanism of formation of parabolic cracks and the specific shape of the defect that the bullet produces in the flat bones. The dynamic load applied by means of an indentor forms at a higher rate than the velocity of sound in the affected material. It gives reason to consider the effect of a bullet moving with the speed of 250 m/s as quasi-static loading. The results obtained in this study make a contribution to the theory of impact effect of a bullet and provide a deeper insight into the physical nature of the direct and sideway action of a gunshot projectile. Moreover, they explain the cause behind the widening of the outlet part of the perforating fracture in the flat bones.