The platysma is a superficial muscle that overlaps the sternocleidomastoid. It is a broad sheet arising from the fascia covering the upper parts of the pectoralis major and deltoid; its fibers cross the clavicle, and proceed obliquely upward and medially along the side of the neck.
For example genetic differences, females inherit X chromosomes from their father giving them a genetic make-up of XX, while males inherit a Y chromosome from their father, thus giving them a genetic make-up of XY.
Sexual Identity - the degree of awareness and recognition of sex and sex roles. Gender - behaviors or patterns of activities that a society or culture deems appropriate for men and women. Definitions (cont.) Gender Role - the degree to which a person adopts the gender-specific behaviors ascribed by his or her culture. Gender Identity - the degree to which a person has awareness or recognition that he or she adopts a particular gender role.