Emedinews: Insights on Medicolegal issues - Hair and fiber, found on human body or at the scene of crime, are commonly used in investigation in cases of assaults, sexual offences, bestiality

·         Hair comprises mainly two parts: Shaft is the part above the skin; root lies below the skin. The root has a bulb as a base, embedded in hair follicle. The cuticular scales cover the shaft. The shaft has two layers: outer one is called cortex, and the inner one medulla.

·         The hair pigment is present in the cortex. The cuticular scales present around the cortex are non-nucleated cells originating from follicle, and are keratinized. The medulla consists of cylinder-like cells produced by matrix cells. The ratio of medullar diameter to that of the shaft is known as medullar index.

·         The medullary column is present in the centre of the cortex. The pigment granules present in the cortex consist of melanin. It is made up of several units of monomer, consisting of indole and quinone. It contains amino acids like dihydroxy phenylalanine and tyrosine.

·         The medullar cells contain large amount of glycogen.

·         Macroscopic and microscopic examination of hair is done in the Forensic Laboratory, to distinguish it from fiber and to ascertain whether the hair is of a human hair or an animal and to fix the individual identity.

(Contributed by Dr Sudhir Gupta)