Anagen / Catagen / Telogen
Definition
Hair growth phases. Anagen is the active growing phase (about 85 percent of scalp hairs), catagen the brief transition, telogen the resting phase (about 10 to 15 percent) ending in shedding with a club-shaped root.
- Anagen proportion
- About 85% of scalp hairs
- Catagen role
- Brief transition phase
- Telogen proportion
- About 10-15% of scalp hairs
- Telogen root shape
- Club-shaped
Common questions
How does an examiner use these proportions in casework?+
The mix of phases recovered from a scene or item can be compared against expected population proportions; an unusual concentration of anagen hairs, for example, may suggest forcible removal rather than normal shedding, informing how the hair evidence is interpreted.
Why is the club-shaped root a useful visual cue microscopically?+
It is a distinctive, easily recognised morphology under low magnification that lets an examiner sort telogen hairs from anagen or catagen hairs quickly, before deciding which specimens are worth prioritising for DNA extraction.
Related terms
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- Medulla
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- Medullary Index
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- Natural Fibre
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- Synthetic Fibre
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