Breast augmentation
The modern prosthetic breast was invented in 1961, by the American plastic surgeons Thomas Cronin and Frank Gerow, and manufactured by the Dow Corning Corporation; in due course, the first augmentation mammoplasty was performed in 1962. There are five generations of medical device technology for the breast-implant models filled with silicone gel; each generation of breast prosthesis is defined by common model-manufacturing techniques.
Puberty
The first physical sign of puberty in girls is usually a firm, tender lump under the center of the areola of one or both breasts, occurring on average at about 10.5 years of age. This is referred to as thelarche. By the widely used Tanner staging of puberty, this is stage 2 of breast development (stage 1 is a flat, prepubertal breast). Within six to 12 months, the swelling has clearly begun in both sides, softened, and can be felt and seen extending beyond the edges of the areolae. This is stage 3 of breast development. By another 12 months (stage 4), the breasts are approaching mature size and shape, with areolae and nipples forming a secondary mound. In most young women, this mound disappears into the contour of the mature breast (stage 5), although there is so much variation in sizes and shapes of adult breasts that stages 4 and 5 are not always separately identifiable.