During puberty, the breast grows in consequence to the influences of the hormones estrogen and progesterone; as a mammary gland the breast is composed of lobules of glandular tissue, each of which is drained by a lactiferous duct that empties to the nipple. Most of the volume (ca. 90%) and rounded contour of the breasts are conferred by the adipose fat interspersed amongst the lobules – except during pregnancy and lactation, when breast milk constitutes most of the breast volume.[1]