U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Back to the OSAC Lexicon

Cross-sectional Shape

the shape of a hair shaft when cut at a right angle to its longitudinal axis.

Discussion—When viewed longitudinally with transmitted light, the apparent cross-sectional shape is deter- mined by slowly focusing through the hair (optical cross- sectioning). When viewed longitudinally between crossed polars, the cross-sectional shape can be determined by observ- ing the interference colors.

Committee
Trace Materials
Date Added to Lexicon
Standard Source (Designation Number Title of Standard. Publisher, Place, Year.)
ASTM E3175-23 Standard Practice for Training in the Forensic Examination of Hair by Microscopy. ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428, 2023. Source link
Reprinted, with permission, from ASTM, copyright ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428. A copy of the complete standard may be purchased from ASTM International, https://www.astm.org