To understand how the breast is built, we must examine its scaffolding, and then add intervening components. Let’s pretend we are building breasts. First we’ll start by making the skin on the chest wall loose, in a manner of a conical tent. We will make it as loose as we need to fill it with the volume we desire. Then, we’ll build the scaffold. Picture branching lines of connective tissue (white, fibrous, scar like strands) that attach the covering of the chest wall muscle to the overlying skin. Now if you were to tent up on the loose skin in the center of the breast, the scaffold would only allow you to stretch to the limits of it length. This is what would limit the descent of your breasts via gravity, though eventually the scaffold would stretch, and cause sagging breasts. Tenting the scaffolding would also make spaces between its individual strands. The spaces will then be filled with breast parenchyma, or the breast tissue that is responsive to female hormones, produces secretions, swells with monthly cycles, and makes milk. Each segment of this breast tissue will then have a pipe to drain its secretions, or milk. The pipes would travel to the nipple, and get bigger, the nearer to the nipple they came as more pipes joined in from other parts of the breast, and would look like an upside down tree. Finally, a several centimeter layer of fat would be placed under the skin, between the breast parenchyma (tissue), and the skin. The thickness of the fatty padding would depend on the bodyfat composition of the recipient of our breast.