Cuticle Scale Patterns

A small clump of hair was recovered from a murder victim who was holding onto the clump of hair. The first step is to determine the color, length, and diameter of the hair found. The shape and color intensity of pigment granules can be different if the hair has been dyed or bleached. Dyed hair has color in the cuticle and cortex; bleaching removes pigment and gives a yellow tint. Then, determine if the hair found is human hair or animal hair by checking the cuticle scale patterns. There are 3 types coronal, spinous, and imbricate. Coronal scale pattern is rarely found in humans and is usually found in small rodents and bats. Spinous scale pattern is never found in humans and is usually found in cats, seals, and other animals. Imbricate scale pattern is found in human and animal hair. As long as the hair found does not have a spinous scale pattern, more analysis needs to be done to determine if the hair is human. …show more content…
The ratio of most animals is ½ and the ratio for humans is 1/3. Medulla patterns are also important, there are 3 types continuous, interrupted, and fragmented. The continuous pattern is found in human pubic hair, animal hairs and mongoloid race hairs. The interrupted pattern is found in animal hairs. The fragmented pattern is found in human head hair except for the mongoloid race. Human hair can have an absent medulla. Then, it is important to analyze the medulla shapes which range from cylindrical, which is seen in human hair, to a string of pearls. Compared to animal hair, a human hair is fine and thin and has pigment that is evenly