The best known of these surgeries are those that reshape the genitals, which are also known as genital reassignment surgery or genital reconstruction surgery (GRS). The meaning of sex reassignment surgery usually differs for transwomen (male to female) rather than transmen (female to male). For transwomen, sex reassignment usually involves the surgical construction of a vagina, whereas in the case of transmen, this term may entail any of a variety of procedures, from the mastectomy (removal of the female breasts) to the shaping of a male-contoured chest to the construction of a penis. Additionally, transmen usually undergo a hysterectomy and bilateral salpingo-oophorectomy.