Chapter 12: Forensic Hair Analysis

Anagen

Actively growing phase of the hair; the follicle produces new cells and pushes them up the hair shaft as they become incorporated into the structure of the hair.

Medulla

Appears as if a small explosion occurred in the middle of the hair and may be found singly or in multiples.

Pigment granules

________ are found in the cortex and are dispersed variably throughout the cortex.

Follicle

The structure within which hairs grow; it is a roughly cylindrical tube with a larger pit at the bottom.

Cortical Fusi

Small bubbles that may appear in the cortex; when they do appear, they may be sparse, aggregated or evenly distributed throughout the cortex.

Subshield Stricture

A narrowing of the hair to slightly less than the normal, nonshield shaft diameter.

Vibrissa

The technical term for whiskers, the short to long, stiff, often white hairs around the snout and muzzle.

Keratin

A tough protein- based material from which hair, nails, and horns are made in animals.

Pili Annulati

Hairs with colored rings.

Accuracy

Proportion of true results.

Root

The portion that formerly was in the follicle, the proximal most portion of the hair.

Ovoid Bodies

Odd structures that look like very large pigment granules.

Precision

Proportion of true positives against all positive results.

Monilethrix

Makes hairs look like a string of beads.

Pheomelanin

Lighter pigment.

Specificity

True negative rate.

Imbricate

Human scale pattern.

Melanocytes

Specialized cells in the follicle producing small colored granules that give hairs their particular color.

Pili Torti

Monilethrix makes hairs look like a string of beads.

Catagen

Transitional phase of the hair; the follicle begins to shut down production of cells, the cells begin to shrink, and the root condenses into a bulb-shaped structure called a root bulb or a club root.

Cortex

Consists of spindle-shaped cells (fusiform) that contain or constrain numerous other structures.

Eumelanin

Dark brown pigment.

Hairs

A particular structure common only to mammals; they are the fibrous growths that originate from their skin.

Cuticle

A series of overlapping layers of scales that form a protective covering.

Scissor cut hair

________ has a clean, straight border, whereas razor-cut hair is angled.

Fur Hairs

Thinner and softer which fill in the rest of the coat providing warmth and bulk.

Hairs

A particular structure common only to mammals; they are the fibrous growths that originate from their skin

Keratinization

the hardening process of hair growth

Pili Arrector

Hair muscles

Anagen

Actively growing phase of the hair;  the follicle produces new cells and pushes them up the hair shaft as they become incorporated into the structure of the hair

Melanocytes

Specialized cells in the follicle producing small colored granules that give hairs their particular color

Telogen Phase

the resting phase for the follicle

Shaft

The main portion of the hair

Tip

The distal most portion of the hair

Cuticle

A series of overlapping layers of scales that form a protective covering

Imbricate

Human scale pattern

Cortex

Consists of spindle-shaped cells (fusiform) that contain or constrain numerous other structures

Cortical Fusi

Small bubbles that may appear in the cortex; when they do appear, they may be sparse, aggregated or evenly distributed throughout the cortex

Ovoid Bodies

Odd structures that look like very large pigment granules

Medulla

Appears as if a small explosion occurred in the middle of the hair and may be found singly or in multiples

Guard Hairs

Large, stiff hairs that make up the outer part of the animals coat

Transitional Body Hairs

Hairs that do not fit into these categories; such as  those on the stomach, between the chest and the pubic region

Buckling

an abrupt change in direction of the hair shaft with or without a slight twist

Shouldering

an asymmetrical cross section of hairs

Sensitivity

True positive rate

Specificity

True negative rate

Negative predictive value (NPV)

Proportion of true negatives against all negative results

Accuracy

Proportion of true results