Anatomically, the breasts are non-rigid areas of glandular tissue, with few foothold structures, such as connective tissue. Breasts are composed of the mammary glands, which remain relatively monophonic throughout life, as well as the adipose tissue or heavy tissue that surrounds the mammary glands.

It is the heap and distribution of adipose tissue and, to a lesser extent, glandular tissue that leads to variations in breast size. In addition, the breasts contain centralized ligaments, although their exact Sexy Bras function as related to breast support is controversial. These ligaments, and the overlying skin (referred to as the dermal brassiere) hand determine the resulting breast shape.