TY - CHAP M1 - Book, Section TI - Hair Disorders A1 - Hordinsky, Maria K. A2 - Soutor, Carol A2 - Hordinsky, Maria K. Y1 - 2017 N1 - T2 - Clinical Dermatology AB - The hair follicle is a complex structure which produces the hair fiber consisting of a cortex, medulla, and cuticle (Figures 19-1 and 19-2). Hair follicles demonstrate the unusual ability to completely regenerate themselves. Hair grows, falls out, and then regrows. In the normal human scalp, up to 90% of hair follicles are in the growth phase called anagen, 1% in the transition phase catagen, and up to 10% in telogen or the loss phase. The anagen phase lasts approximately 3 years, catagen 2 to 3 weeks, and telogen 3 months.1 SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/29 UR - dermatology.mhmedical.com/content.aspx?aid=1177005978 ER -