Hair Anatomy
This is the outermost layer of the hair shaft with overlapping scales.
Cuticle
How long does hair grow each month?
1 cm
Fibers are considered this category of evidence.
Class evidence
Wool, cotton, and silk are examples of these fibers.
Natural fibers
Hair can be used to do this when examining suspects.
Include or exclude suspects
This layer contains pigment granules that give hair its color.
Cortex
Hair evidence is considered this type of evidence: class or individual?
Class evidence
Smallest unit of a textile material.
Fiber
Nylon and polyester are examples of these fibers.
Synthetic fibers
Burning synthetic fibers typically leaves behind this type of residue.
Hard bead
This central core can be continuous, fragmented, or absent.
Medulla
This forensic principle explains why hair transfers easily.
Locard’s Exchange Principle
Fibers from animals or plants fall into this classification.
Natural fibers
These fibers melt when exposed to flame.
Synthetic fibers
Hair alone cannot do this without DNA from the root.
Identify a specific individual
This part of the hair contains nuclear DNA used for identification.
Root (follicle)
Name one microscopic hair characteristic used for comparison.
Medulla type OR scale pattern OR pigment distribution
This tool helps forensic scientists view fibers close‑up.
Microscope
These fibers show more varied diameter and texture.
Natural fibers
This test determines whether a fiber dissolves in certain chemicals.
Solubility test
Humans typically have this type of medulla pattern.
Fragmented or absent
A proper hair comparison requires examining at least how many hairs?
50–100 hairs
Fibers help link these three things in a crime.
Suspect, victim, and crime scene
Under a microscope, this fiber looks smooth, uniform, shiny/glassy
Synthetic
Explain why hair and fiber evidence are powerful when used together, even though each is class evidence.
Together they create a pattern of associations (multiple transfers, matching locations, supporting circumstances) that strengthens links between the suspect, victim, and crime scene.