A hair is found at a crime scene and you are asked to evaluate whether it is of human origin. Which of the following attributes indicates that the hair will be of human origin?
The cuticle completely covers the hair shaft in human hair. It only paly covers the hair shaft in animal hair. Human hair has 3 pas: Cuticle - outermost layer; Coex - middle layer; Medulla - innermost pa. Coex is thick (4 - 10 times that of medulla) such that the medullary index is <0.3 (Medullary index=diameter of medulla/diameter of hair). The pigment in human hair is present only in the coex, where it is evenly distributed. Reference The Synopsis of FORENSIC MEDICINE and Toxicology 29th Edition
Medullary index of 0.5
Cuticle completely covers hair shaft
Pigment granules present in coex and medulla
Medullary index of 1
Miscellaneous