1070 



URIXARY AXD REPRODUCTIVE ORGANS 



lobes of somewhat ]iynniiidal form, with their bases at the periphery and the apices 

 converging towards the mannnilla. They are held together and sui)i)()rted by a 

 fibrous capsule, whicli sends inwards deep interlobular processes, to form a loculated 

 framework for the glandular elements; and superficial jn-ocesses running to the 

 skin and enclosing supra-mammary fat-containing spaces or adipose fossae. The 

 posterior asjiect of the capsule also encloses other fat-spaces (retro-mammary) and 

 is attached to the deep fascia over the pectoralis major by loose connective tissue, 

 the bands of which may be separated by large lymph-si)aces, the so-called 'sub- 

 mammarv liursre.' Finally, isolated collections of fat ( intra-mammary) may be 

 found buried amidst tlie "lobules of the gland. It is the fat lying in the sub- 

 cutaneous adipose fossic and between the gland lo))ules that gives smoothness and 

 uniformity of surface to the breast, and when it becomes al)sorl)ed during lactation 

 or in conditions of emaciation, the lobular structure of the gland is distinctly 

 manifest. 



Structurally each of the component lobes may be regarded as a modified sebaceous 

 gland, and hence an appendage of the skin. Each is provided with a single 

 excretory tube (lactiferous or galactophorous duct), Avhich on approaching the 



Fig. 657.— The Female Mamma dueixg Lactation. (After Luschka.) 



Ampulla of duct 



Acini of gland 



Y Adipose loculus 



Gland loculus 



nii)ple is dilated into a sinus or ampulla, and finally ends by a constricted orifice 

 at the ajiex of the nipple. The acini and smaller tubes are lined with cubical 

 epithelium, which becomes replaced by columnar cells in the excretory ducts. 



Accessory glands of small size— half a line to two lines in diameter, and to the 

 number of five to fifteen — are normally found under the skin of the areola, and 

 open on to the summit of the nip|»le. 



The gland as a whole is not circular in outline, l)ut usually presents three cusjis 

 — one towards the sternum, scmietimes overlap])ing the bone; the others towards 

 the axilla, one above and the other below; smaller extensions, moreover, pass from 

 the base of tlio gland to the deep fascia, and may pierce it and lie upon or in the 

 fibres of the pectoral muscle (Heidenhain). These processes are commonly left 

 behind in amputation of the l^-east, and may form nuclei for recurrent growth in 

 malignant disease. 



The mammilla and areola are specially modified ]iortions of the mammary 

 integument. The mammilla is placed a little internal and inferior to the centre 

 of the gland, and ]K)ints forwards and outwards. It is of somewhat conical form, 

 averaging about half an inch in length, and terminating bv a rounded extremity 

 which is pierced by the orifices of the lactiferous ducts. It" is of pinkish colour. 



