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Hair Analysis. Identification of species through microscopy. Collection of Hair Specimen. Examination of the Medulla. Patterns in Animal Species. Examination of Scale Pattern. Human Hairs. Racial Determination. African. Asian. European. Hair Roots.
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Hair Analysis Identification of species through microscopy.
Patterns in Animal Species Examination of Scale Pattern
Human Hairs • Racial Determination African Asian European
Hair Roots Pulled Forcibly Removed Shed
Tip of the Shaft Burned Cut Razored Split
Identification of Hair Differentiation between human and animal hair
MEDULLA The medulla is the core of a hair – it is, however, not always present. There are several types and patterns. TYPES: Continuous—most animals (seldom humans) Intermittent or interrupted (mostly medulla with some gaps)— human pubic hair, sometimes head hair Fragmented (mostly gaps with some medulla)—mostly human hair Absent—human head hair only
Uniserial--small blocks in a row Vacuolated--uneven pattern Medula Patterns Multiserial--several rows of blocks Lattice--circular patterns Amorphous--without a specific pattern
HAIR MEDULLA Cow Cat Horse Muskrat Rabbit -- Multiserial Rabbit -- Uniserial Goat Dog Bat
Medulla: Present Medullary Index: More than 1/2 Medulla Pattern: Vacuolated Species: Goat
Medulla – present • Medullary Index – more than ½ • Medulla Pattern – Vacuolated/amorphous • Root – Spade - shaped • Species: Dog
Medulla – present • Medullary index – more than ½ • Medulla pattern – multiserial • Species -- Rabbit
Human or animal? • Medulla – present • Medullary Index – more than 1/2 • Medulla pattern – uniserial • Root -- frayed • Species -- Cat
Now Take a look at some slides of different kinds of hair, straight from the FBI. Can you guess what hair is human and what hair isn't?
No 1 is human head hair of Caucasian origin. Caucasian hairs come in the widest variety of colors, can be of fine to medium coarseness and are generally straight or wavy. In addition, the shafts vary from round to oval in cross section. Finally, color pigments are fine- to medium-sized and are evenly distributed throughout the shaft. Hair #1
Hair # 2. • This is a deer hair. Unlike that of any other animal, the root of deer hair has a wine-glass shape: a narrow root that gradually widens. In addition, the medulla, or inner layer of cells, consists of spherical cells that take up the whole width of the hair in a repeating pattern of different shapes, such as a hexagonal shape, depending on what member of the deer family the subject belongs to.
Hair #3 • This is a human head hair of Afro-Caribbean origin. Such hairs are generally curly or kinky, and have a flattened cross section. Larger than those of other racial groups, its pigment particles are grouped in clumps of different sizes and shapes and may be so dense that they render the hair opaque. Furthermore, the hair shaft may vary — or seem to vary — in diameter because of its flattened nature and the way it settles on the microscope slide
Hair #4 • This is a cat hair. Cat hair has fibrous roots and its pigment particles do not run down to the root. In addition, its medulla, or inner layer of cells, is thicker than that of dog hair.
Hair #5 • This is a human head hair of Asian origin. Such hair is generally coarse, straight and circular in cross section. Its diameter is wider than the hair of other racial groups, and the outer layer of the hair, the cuticle, is usually significantly thicker. The medulla, or inner layer of cells, is continuous and wide. In addition, the hair shaft contains pigment particles that are generally larger than those of Caucasian hairs, and often appear to be grouped in patchy areas. Finally, the hair may have a reddish appearance, a product of its pigment.
Hair #6 • This is a dog hair. Dog hair has spade-like roots and its pigmentation runs down throughout the shaft to the root. Its medulla, or inner layer of cells, is thinner, too, than that of cat hair.
CUTICLE SCALES Mosaic Pectinate Imbricate Petal Diamond Petal Chevron http://phs.psdr3.org/science/forensics/traceevidence.html
Cuticle Scales • HUMAN CUTICLE SCALES • DOG CUTICLE SCALES
Answer: NO! The body will dehydrate soon after death, shrinking as a result. The fingernails and hair will appear to grow. Just an optical illusion!!