Physiology and Anatomy of Hair in Drug Abusing Cases

To interpret the results of hair analysis tests accurately and to understand the appropriate role of hair analysis in drug abuse testing and solve instances of poisoning, drug and substance abuse, a basic knowledge of the biology of hair is essential. In case of poising by heavy metals, the hair retains traces of poison for a considerable period. Chemical examination of hair in such cases will reveal the presence of poison in the living as well as exhumed whose biology is only partially understood. Hair grows from small organs (follicles-a skin organ which produce hair) located within the complex microenvironment of the skin which has multiple layers of tissue, three glands whose secretions bathe hair, and multiple vascular systems which are capable of transferring drugs to hair at many levels along the path of the hair shaft. The advantages and disadvantages of using pubic, scalp and beard hair as specimens for hair analysis are also considered. A more precise understanding of the mechanisms involved in the incorporation of drugs into hair is critical for forensic scientist in order to interpret the results of hair analysis properly.