The glamor of the breast is brought down to earth with a bump by the anatomists who define it as a “modified sweat gland.”
The normal location of the breast (mammary gland) is lateral to the midline, with its central point, the nipple, at the level of the 4th intercostal space, and in post-menarche youth extends in the female between the 2nd and 6th intercostal spaces, lying on the surface of the deep fascia that covers the pectoral muscles. With age and pregnancy the breast may become pendulous, but its base does not move.
The milk line from the axilla to the groin is a potential for nipples or vestigial breaststo be located elsewhere.
The center of the breast is marked by the colored conical nipple and its surrounding areola; elsewhere the breast is smooth, and usually in the female bears few hairs. The outer coat is normal skin, with a varying degree of fatty tissue in the subcutaneous layer.
The gland tissue is constructed rather like a grape vine; there are ovoid lobules which in lactation produce the milk; these empty into small ducts which are joined by others until the main stem duct, the ductus lactiferi is formed and leads to the nipple, with an opening much narrower than the duct itself, and usually with a distended lactiferous sinus immediately proximal to the opening. The gland tissue is structured into recognizable divisions, into lobules and lobes by fibrous septa connected to the subcutaneous fascia.
The space between the glandular tissue is filled with fiber and fat. The fibers are organised as supporting ligaments for the breast tissue, named after the anatomist and surgeon, Sir Astley Cooper, and giving cause for the vulgar medical student to refer to the pendulous breast as Cooper’s droop.