In the course of a woman's life, her breasts change in size and volume as the skin envelope becomes inelastic, and the Cooper's suspensory ligaments—which suspend the mammary gland high against the chest—become loose, and so cause the falling forward and the sagging of the breast and the nipple-areola complex (NAC). Moreover, additional to tissue prolapse, postpartum diminishment (involution) of the voluminous milk glands in the breast aggravates the looseness of the suspensory ligaments, and of the inelastic, overstretched skin envelope. Mastopexy corrects said degenerative physical changes, by elevating the (internal) parenchymal tissues, cutting and re-sizing the skin envelope, and transposing the nipple-areola complex higher upon the breast hemisphere. The degree of breast ptosis of each breast is determined by the position of the nipple-areola complex (NAC) upon the breast hemisphere; ptosis of the breast is measured with the modified Regnault ptosis grade scale.