RU2325109C1 - Diagnostic method of internal deformation of hair at mechanical influence - Google Patents

Abstract

FIELD: medicine; forensic medical examination of material evidences.

SUBSTANCE: microscopic examination of hair in passing and polarised light is carried out. Thus at hair microscopy in passing light places of possible damage of hair is found, hair in polarised light on an extent is investigated, the maximum display of hair in a dark field is reached, blackout and cleared sites on a homogeneous background of the intact hair shaft is tapped on, they are registered and by that area of internal deformation of hair is defined, than the fact of mechanical influence on it is established.

EFFECT: method provides registration of the latent internal damages of hair.

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Description

The invention relates to medicine, namely to a forensic examination of material evidence, and can be used in the practical work of forensic experts to detect internal hair deformation by microscopy in polarized light and to establish the fact of a mechanical effect on the hair.

As an analogue, a method for comparative study of human hair is proposed by examining them in polarized light [1]. It is based on the assessment of the signs of different colors of gray, blond and dyed hair in polarized light.

The disadvantages of this method is the assessment of the color of the hair rods only in order to establish the fact of dyeing, a comparative study and the possibility of the origin of hair from the head of one person. The question of the fact and types of mechanical effects on the hair in this way cannot be resolved, since the possible methods for studying hair damage under microscopy in polarized light are not indicated.

A known method of establishing the similarity of textile fibers by the polarization properties [2] in order to obtain data on the similarity or difference of the studied fiber with the sample fibers, since they are optically active and are able to change the plane of the light incident on them.

Its disadvantage is the consideration of natural and artificial fibers, and not objects of biological origin, which are hair. This method also does not address the issue of a possible mechanical effect on the fibers and the morphological signs of deformation.

The closest in essence to the proposed method is a method for assessing mechanical stresses arising in bone tissue under model conditions [3]. This method consists in creating a flat bone model from an isotropic material, plexiglass. In crossed polaroids, this model is invisible, because it looks dark. Applying a load, they cause anisotropy of plexiglass, which becomes noticeable in the characteristic pattern of bands and spots. Based on this picture, as well as on its change, conclusions are drawn about the mechanical stresses that arise in the model, and therefore in the bone itself. A common feature is the study of possible deformation using microscopy in polarized light.

Its disadvantage is the determination of the presence of deformation in the model, and not in the biological object itself. The method involves research in an experiment, and not in practical material, the results of which may be different from damage occurring in real conditions. It excludes the possibility of examining hair and deformations arising in them.

The purpose of the invention is the creation of a method for recording internal damage to the hair. With various types of mechanical effects on the scalp, hair damage is formed, according to the properties of which one can speak out about the possible conditions and mechanisms of their formation. However, the deformation of the hair is not always visible in the transmitted light of the microscope and therefore remains unnoticed. The use of microscopy of the hair in polarized light allows you to detect areas of latent deformation of the hair in the form of areas of darkening or enlightenment on a uniform background of an intact shaft and thereby establish the fact of mechanical effects on the hair.

The proposed method is as follows:

- hair taken from the surface of the gun, from the wound of the scalp or from the scene of the incident, and hair samples from the victim’s head are washed in distilled water or physiological saline, placed on a glass slide in a drop of distilled water parallel to the stage in a straight line, without bends and twists in one plane;

- covered with a coverslip, examined in transmitted light using a microscope, while studying the morphological features of the hair, visible damage and the location of the alleged deformation of the rod;

- they study hair in polarized light, for which they place a glass-polarizer in front of the condenser, and the analyzer in the tube between the lens and the eyepiece. By rotating the stage around the optical axis of the microscope and rotating the glass polarizer, the maximum dark field of view and the best display of the hair in the field of view are achieved;

- examine hair samples in polarized light, reveal structural features of the rods of intact hair;

- examine the hair, presented as evidence, in a polarized light, against the background of a uniform color of the intact hair shaft, identify areas of dimming, enlightenment, register them, thereby determining the area of internal deformation of the hair, thereby establishing the fact of mechanical impact on it.

The drawing shows the hair during microscopy in transmitted and polarized light from a microscope. The drawing has the following notation: 1 - a hair shaft with internal deformation in transmitted light, 2 - the same hair shaft segment in polarized light, 3 - an undamaged hair shaft segment in polarized light, 4 - dimming and enlightenment (internal deformation) sections in polarized light.

Example 1. A metal frying pan was received for examination as material evidence, which, according to the circumstances of the case, was hit on the man’s head. There was whole hair on the bottom of the pan, which, when examined in transmitted light from a microscope, was not damaged. When examining some hair in polarized light, the following was observed along the length: the main thickness of the shaft was uniformly yellow in color, and dimming in the form of a “bead” was found in several sections of the hair, which indicated internal damage to the hair shaft, which established the fact of mechanical action on the hair.

Example 2. A metal strip was removed from the scene of the incident, which, according to the circumstances of the case, hit the head of a man whose corpse was burned, which excluded the possibility of examining head wounds. On a metal strip stereomicroscopy in a trace of dried blood was found gray hair torn male male sex, in which when examined in transmitted light, no damage was found. When studying the hair shaft in polarized light against a background of a uniform, uniform yellow hair background, areas of darkening and enlightenment were detected, which were registered as areas of internal deformation, which established the fact of mechanical action on the hair.

The above phenomenon was recorded in 70 observations from practice, as well as in 1050 experimental hair injuries.

Practical observations and experimental data have significant differences from the prototype: the developed method involves the study of a biological object directly - the hair, and not its model, the detection of internal deformation in polarized light allows us to establish the fact of mechanical effects on the hair, which is important in solving forensic issues about the mechanisms of damage development.

Thus, the invention establishes that with various types of mechanical effects on the scalp, hair damage is formed, by examining the properties of which the expert determines the possible conditions and mechanisms of their formation, and therefore reconstructs the circumstances of the injury. However, often the internal deformation of the hair is not detected in the transmitted light of the microscope and therefore remains unnoticed, which leads to the erroneousness of expert conclusions. The use of microscopy of the hair in polarized light allows you to detect the area of latent deformation of the hair in the form of areas of darkening or enlightenment on a uniform background of an intact shaft and this confirms the fact of mechanical effects on the hair. The importance of the invention for practical use lies in the fact that in forensic practice, injuries with blunt solid objects of the scalp are often found and in most cases are accompanied by fractures of the bones of the cranial vault and damage to the hair. In this case, damaged hair is found in the wound, on the gun, at the scene, the properties of hair damage are of diagnostic value in assessing the mechanisms of injury and the identification of the gun. For the application of the invention does not require large material costs for equipping the laboratory, since the study involves the use of a biological microscope with the attached polarizing filters. The proposed method can be used in forensic medicine when conducting examinations of material evidence.

Information sources:

1. Tatarenko V.A., Chernogo E.I. On the possibility of using polarized light in a forensic comparative study of human hair / V.A. Tatarenko, E.I. Cherney. Sat scientific Proceedings of the Kharkov honey. in-that. - Kharkov, 1968.- t. 78, p. 137-140.

2. Zagryadskaya A.L. Methods for the detection and study of overlays of animal tissue cells and textile fibers from clothing materials on injury instruments and other objects / A.L. Zagryadskaya. Laboratory and special research methods in forensic medicine. - M., 1975, - p. 157-179.

3. Remizov A.N. Medical and biological physics / A.N. Remizov. Textbook for honey. specialist. universities. - 3rd ed. corrected - M .: Higher. School, 1999. - c.447-456 - prototype.

Claims (1)

A method for diagnosing internal deformation of hair under mechanical stress, including microscopic examination of the hair in transmitted and polarized light, while microscopy of the hair in transmitted light searches for places of possible damage to the hair, examines the hair in polarized light along the length, reaches the maximum display of the hair in a dark field, reveals against a uniform background of an intact hair shaft, the areas of dimming and enlightenment, register them and thereby determine the area of internal deformation and the hair than to establish the facts of mechanical impact on him.

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