These examinations should be conducted only by a properly trained hair examiner employing a side-by-side comparison of a questioned hair and a known sample. Three general conclusions can be reached as a result of microscopic hair analysis: exclusion, no conclusion, or association.
- 1 What are the three properties that need to be identified when comparing two hair samples?
- 2 What are three different things that hair can help determine?
- 3 What are the three most important features of hair used for identification?
- 4 What are some things that can be determined by hair evidence?
- 5 What are 3 macroscopic properties of hair?
- 6 What are the 3 common scale patterns?
- 7 What are the 3 phases of the hair life cycle?
- 8 What conclusions can be drawn from microscopic hair analysis?
- 9 What are the 3 parts of the hair shaft?
- 10 How is hair evidence analysis?
- 11 How do you compare hair samples?
- 12 What is hair comparison microscopy?
- 13 How are hairs identified and compared?
What are the three properties that need to be identified when comparing two hair samples?
The color, shape, and distribution of these granules provide the criminalist with important points of comparison among the hairs of different individuals.
What are three different things that hair can help determine?
Forensic scientists perform three major types of hair analysis. Chemical assays are used to assess the use of illegal drugs, to screen for the presence of heavy metals in the body, and to test for nutritional deficiencies. The root of the hair has cells that contain DNA , which can be used for DNA analyses.
What are the three most important features of hair used for identification?
A hair is a fibrous outgrowth from the skin of mammals and consists of three anatomical regions, the cuticle, medulla and cortex. Characteristics within these regions are used to determine whether the hair is human or animal, racial origin and body area.
What are some things that can be determined by hair evidence?
Hair – Analysts can tell investigators if individual hairs are human or animal, and in the case of human hair, where on the body the sample originated. Samples can be tested to determine the color, shape and chemical composition of the hair, and often the race of the source individual.
What are 3 macroscopic properties of hair?
Length, color, and curliness are macroscopic characteristics. Microscopic characteristics include the pattern of the medulla, pigmentation of the cortex, and types of scales on the cuticle (Figure 3-12).
What are the 3 common scale patterns?
There are three basic scale structures that make up the cuticle—coronal (crown-like), spinous (petal-like), and imbricate (flattened).
What are the 3 phases of the hair life cycle?
At any given time, a random number of hairs will be in one of three stages of growth and shedding: anagen, catagen, and telogen. Anagen is the active phase of the hair. The cells in the root of the hair are dividing rapidly.
What conclusions can be drawn from microscopic hair analysis?
Three general conclusions can be reached as a result of microscopic hair analysis: exclusion, no conclusion, or association.
What are the 3 parts of the hair shaft?
Each hair shaft is made up of two or three layers: the cuticle, the cortex, and sometimes the medulla. The cuticle is the outermost layer. Made of flattened cells that overlap like the tiles on a terra-cotta roof, the cuticle protects the inside of the hair shaft from damage.
How is hair evidence analysis?
Because hairs can be transferred during physical contact, their presence can associate a suspect to a victim or a suspect/victim to a crime scene. The types of hair recovered and the condition and number of hairs found all impact on their value as evidence in a criminal investigation.
How do you compare hair samples?
Forensic analysts use an instrument called a comparison microscope to view a known hair sample and an unknown sample alongside one another to see if they share similar characteristics and could have come from the same source.
What is hair comparison microscopy?
Microscopic hair comparison is basically what it sounds like: a forensic analyst compares one or more hairs relevant to a crime. One or more of the hairs is unknown, and one or more are known to come from a specific person.
How are hairs identified and compared?
The body area from which a hair originated can be determined by general morphology. Length, shape, size, color, stiffness, curliness, and microscopic appearance all contribute to the determination of body area. Pigmentation and medullar appearance also influence body area identification.