Human anatomy (gr. ἀνατομία, "dissection", from ἀνά, "up", and τέμνειν, "cut") is primarily the scientific study of the morphology of the human body. Anatomy is subdivided into gross anatomy and microscopic anatomy. Gross anatomy (also called topographical anatomy, regional anatomy, or anthropotomy) is the study of anatomical structures that can be seen by the naked eye. Microscopic anatomy is the study of minute anatomical structures assisted with microscopes, which includes histology (the study of the organization of tissues), and cytology (the study of cells). Anatomy, human physiology (the study of function), and biochemistry (the study of the chemistry of living structures) are complementary basic medical sciences that are generally together (or in tandem) to students studying medical sciences.
In some of its facets human anatomy is closely related to embryology, comparative anatomy and comparative embryology, through common roots in evolution; for example, much of the human body maintains the ancient segmental pattern that is present in all vertebrates with basic units being repeated, which is particularly obvious in the vertebral column and in the ribcage, and can be traced from very early embryos.
Facial hair is a secondary sex characteristic of human males. Men typically start developing facial hair in the later years of puberty or adolescence, between seventeen and twenty years of age, and most do not finish developing a fully adult beard until their early twenties or later. This varies, as boys may first develop facial hair between fourteen and sixteen years of age, and boys as young as eleven have been known to develop facial hair. In addition, the patches of hair can vary between bushy and bristly. Women are also capable of developing facial hair, especially after menopause, though typically significantly less than men.
Male pogonotrophy (the growing of facial hair; i.e., beardedness) is often culturally associated with wisdom and virility. Men may style their facial hair into beards, moustaches, goatees or sideburns; others completely shave their facial hair. The term "whiskers," when used to refer to human facial hair, indicates the hair on the chin and cheeks.