THE MAMMARY GLAND 



1431 



nipple is rendered rough by fissures (Fig. 1190), it exhibits a depression in which 

 are the openings of the milk ducts (Fig. 1192), and its circumference is thrown 

 into concentric ridges (Fig. 1192). The nipple is surrounded by a darker circular 

 wrinkled area, the areola (areola mammae) (Figs. 1190 and 1191), which contains 

 sweat glands and on which are twelve or fifteen small rounded elevations. These 

 elevations are caused by cutaneous sebaceous glands which in structure represent 

 a transition between sebaceous and mammary glands. They are probably 

 rudimentary portions of the mammary gland and are known as the glands of 

 Montgomery (glandulae areolares) (Fig. 1192). The color of the nipple and areola 

 varies with the complexion of the individual. In brunettes it is darker than in 

 blondes. The usual color of the nipple in a young woman is rosy-pink, the areola 

 being of a darker shade. During the early months of pregnancy the nipple 

 and areola become dark brown in color, the areola becomes larger in circumference, 

 and the glands of Montgomery increase in size (Fig. 1193). The nipple contains 

 nonstriated muscle, and mechanical irritation or sexual excitement makes it stiff 

 and erect. The skin covering the breast is clear, soft, and delicate, and sub- 

 cutaneous veins are often visible. The skin of the nipple and areola is particularly 

 delicate. 



Nipple. 



Areola. 



Lobule unravelled. -- ^ Ampulla. 



Lobule. Loculi in connective tissue. 



FIG. 1190. Dissection of the lower half of the female breast during the period of lactation. (From Luschka.) 



Variations in the Mammae. Before puberty the glands are small, are of the 

 infantile type, grow slowly, and differ but slightly from the male organs. The 

 nipple is small, flat, and pale. At puberty the increase in the size of the breast 

 is rapid and considerable, due to growth of gland tissue and of subcutaneous 

 fat. In the young virgin the breasts are of hemispherical form and of firm con- 

 sistency. During pregnancy the breasts enlarge greatly and remain very large 

 throughout lactation. This' enlargement is due to new gland tissue and increased 

 vascularity. Numerous blue veins are visible in the skin, the areola darkens, 

 and the glands of Montgomery enlarge (Fig. 1193). After the termination 

 of lactation the breasts diminish in size. -They do not become as small as the 

 virgin breast, are apt to lose their hemispherical outlines, and become soft and 



