14 32 THE URINOGENITAL ORGANS 



flabby. They droop as flaccid pendulous masses, the subcutaneous fat is largely 

 gone, and the outlines of the lobular breast tissue can be seen and felt. The 

 nipple is long and hangs down like a teat. At the menopause the breast usually 

 shrinks. In some cases, however, it actually increases in size. In such a case, 

 although the gland atrophies, there is an extensive deposit of fat. In old age the 

 glands undergo atrophy and largely disappear, the skin is flabby and thrown 

 into wrinkles, and the breasts contain very little glandular structure, and are hard 

 from the presence of fibrous tissue. The nipples become pigmented and corru- 

 gated. Women vary greatly in the development of the breasts. In some women 

 they are large, firm, and well proportioned; in others they are small, flat, or 

 atrophy occurs in the course of certain bodily diseases, as in phthisis, and in 

 certain mental diseases, as melancholia. If the ovaries are ill-developed the 

 breasts remain flat and small. The outline and direction of the breast and also 

 of the nipple may be altered by corsets. The left mamma is usually somewhat 

 larger than the right. 



One gland or both glands may be entirely absent, the nipple being also absent. One or both 

 glands may be absent, one or both nipples being present. When there is only one nipple, it is 

 apt to be the left. The term polymazia (mammae accessoride muliebris) means the presence of 

 supernumerary breasts, with or without nipples. Polythelia means the presence of supernu- 

 merary nipples, the associated glandular structure being rudimentary. There may be one, two, 

 or several supernumerary breasts, and when more than one exists, are usually asymmetrical. 

 If one is functionally active, it enlarges during pregnancy and furnishes milk. 



Supernumerary mammae may secrete milk or may be without function. The most common 

 situation is on the part of the chest below and to the inner side of the normally placed gland. 

 They may also exist in the axilla, the abdomen, the groin, the back and the thigh. Many cases 

 of supposed supernumerary glands have been really instances in which moles, warts, or sebaceous 

 cysts have been mistaken for nipples, but some cases are undoubted. 



Prolongations of Mammary Tissue. As previously stated, the outlines of the 

 breast are not regular, but here and there tails, prolongations, or cusps come off 

 from and are true portions of the gland. Two or even more prolongations pass to 

 the edge of the sternum; others pass toward the axilla, the clavicle, and the origin 

 of the External oblique muscle from the ribs. Underneath the mammary gland 

 prolongations of mammary tissue penetrate the pectoral fascia (Heidenhain). If 

 one of the glandular cusps is of considerable size it is called an outlying lobule. 



Structure of Mammary Gland and Nipple (Figs. 1190 and 1191). The glands of the 

 breast (corpus mammae) rest by a smooth posterior surface upon the loose pectoral fascia, which 

 fastens the breast to the muscle beneath, but so loosely that the breast is movable. The mamma 

 consists of gland tissue; of fibrous tissue, connecting its lobes, of fatty tissue in the intervals 

 between the lobes, of retinacula, and of skin. The gland tissue, when freed from fibrous tissue 

 and fat, is of a pale reddish color, firm in texture, generally globular in form, with prolongations 

 here and there, flattened from before backward, thicker in the centre than at the circumference, 

 and presenting several inequalities on its surface, especially in front. On the anterior surface 

 there are many irregular elevated processes with deep spaces between them. From the summits 

 of the elevations connective-tissue strands (retinacula cutis) pass to the true skin. The glandular 

 structure consists of numerous glands divided into lobes (lobi mammae), and these are composed 

 of lobules (lobuli mammae), connected by areolar tissue, which contains the bloodvessels and 

 ducts. The smallest lobules consist of a cluster of rounded alveoli (Fig. 1190), which open into 

 the smallest branches of the excretory ducts; these ducts, uniting, form larger ducts, which 

 terminate in single canals. Each canal is called a lactiferous, galactophorous, or mammillary 

 duct (duetug lactiferus) (Fig. 1190). The alveoli are tubular in form and are lined by low 

 columnar epithelial cells which rest upon a basement membrane. 1 Each glandular area possesses 

 one lactiferous duct. This passes to the apex of the lobe and then into the nipple. The lactif- 

 erous ducts are white and cord-like, and contrast with the yellowish-red tissue of the gland itself. 

 The number of excretory ducts varies from fifteen to twenty, each representing an individual 

 gland. They converge toward the areola, beneath which each duct possesses a spindle-shaped 



1 According to Lacroix and Benda, there is a thin layer of nonstriated muscle between the basement mem- 

 brane and the secreting cell. 



