THE UPPER LIMB 



301 





Lactiferous Duct' 



Ampulla'ti'nt 



them is distinct, and has its own duct. A lobe is made up of lobules, 

 and each lobule is composed of a cluster of tubes, called alveoli or 

 acini, which represent the secreting parts of the gland, and are 

 lodged in spaces known as lociili. The alveolar tubes are lined with 

 cubical epithelium, the cells of which contain fat globules during the 

 period of the functional activity of the organ. The ducts of the 

 lobes are about twenty in number, and are called the lactiferous 



or galactOphOrOUS duets. Mammilla Areola 



They are lined with col- 

 umnar epithelium, and, 

 as they approach the 

 nipple, each presents a 

 dilatation, called the 

 sinus or ampulla. There- 

 after each duct becomes 

 narrow, and enters the 

 nipple to 

 terminate 

 by a minute 

 pore on its 

 summit. 

 The mam- 

 mary glands are present 

 in both sexes, but in the 

 male their development, 

 as a rule, is arrested, so 

 that they are in a rudi- 

 mentan^' condition. 



Bloodvessels of the fig. 

 Mamma. — The arteries 

 are as follows: long 



thoracic (external mammary) of the second part of the axillary; 

 anterior cutaneous or perforating of the internal mammary; and 

 branches from the intercostal arteries of the spaces over which 

 the gland lies. 



The veins pass to the axillary and internal mammary veins. 



Lsrmphatics. — The principal lymphatic vessels of the mammary 

 gland arise in the fibrous stroma, and pass towards the nipple, 

 lying in their course between the galactophorous ducts. In the 

 region around the nipple they terminate beneath the areola in a 

 plexus, called the subareolar plexus. This plexus also receives the 

 cutaneous l^onphatics of the nipple and areola. The efferent vessels 

 from this plexus pass to the antero-internal or pectoral group of axillary 

 glands, more particularly to those on a level with the third rib. 

 ■ There are, however, other paths by which lymph is conveyed 

 I away from the mammary gland, (i) Some IjTnphatics emerge 

 ifrom about the outer two-thirds of the gland, and pass to the 

 Ifedoral group of axillary glands, either directly, or after having 

 [joined the principal honphatics. (2) Other lymphatics (one or 



173. — The Female Mamma during 

 Lactation (after Luschka). 



