CSI Hair

Morphology

The form and structure of hair.

Hair

Protein polymers made up of repeating units, can be natural or synthetic.

Cuticle

The tough, clear covering of the hair shaft.

Imbricate

Refers to a pattern similar to broken glass.

Spinous

A hair structure characterized by bundled spines.

Coronal

A stacked crown pattern found in hair.

Cortex

The middle layer of hair that gives strength, mass, and color.

Keratin

A tough protein polymer made up of 20 amino acids.

Melanin

The pigment that gives color to hair.

Medulla

The spongy interior of the hair shaft.

Fragmentary

Refers to a medulla that is less than half.

Interrupted

Refers to a medulla that is more than half.

Continuous

Refers to a medulla that is entirely present.

Stacked

A term describing multiple scales found only in animal hair.

Human medulla

Can be fragmentary, interrupted, or continuous.

Animal medulla

Can be continuous or stacked.

Medullary index

A ratio of medulla to total hair diameter.

MI for humans

Less than 1/3.

MI for animals

Greater than 1/2.

Round

Head shape characteristic of Asian or Native American hair.

Oval

Head shape characteristic of European, Mexican, or Middle Eastern hair.

Crescent moon

Head shape characteristic of African hair.

Association

The link between an unknown sample and a known sample.

Questioned

A sample of unknown origin.

Exemplar

A sample of known origin.

Metabolite

A product formed by chemical processes in the body.

False positive

When hair absorbs chemicals from its surroundings leading to incorrect conclusions.

Cheiloscopy

The study of lip prints.