Hair Analysis Essay

To start off I will talk about the structure of the hair. First, we have the medulla. The medulla is the innermost layer of the hair shaft. It is the center. Forensic investigators classify hair into five different groups depending on the appearance of the medulla. Next we have the cortex. The Cortex is the largest part of the hair shaft. It also contains the most pigment. Finally we have the cuticle, which is a transparent outer layer of the hair shaft. It looks like scales almost. The cuticle can be used in order to analyze the hair for different toxins, drugs, or metals at specific points in times. It is also used to determine whether the hair is animal or human. There are many different types of medulla patterns. Continuous is one unbroken line of color while interrupted is broken at intervals. Fragmented are when the pigmented lines are unevenly spaced. Solid are when the medulla and the cortex are both pigment filled. None is when there is no separate pigmentation in the medulla. There are also 3 different types of cuticle: imbricate (look like lines, almost like a wall going up), coronal (stacks), spinous (horizontal layers). Other important terms related to hair are: keratin (type of fibrous that make up the majority of the cortex of a hair), melanin granules (bits of pigment found in the cortex), hair follicles (the actively growing root of hair). There is also microscopic variation in hair. The medullary index measures the diameter of the medulla relative to the diameter of the hair shaft. This helps distinguish animal hair from human hair. As said before, there are 3 different types of cuticules (imbricate, coronal, and stacks), which can help narrow down suspects. Cortex color determines the color of the hair, so forensic scientists can determine the color of someones hair with one strand. The diameter of hair can also be determined microscopically and can help the scientist know how thick the suspect’s hair is. Also, once again, it helps