DISSECTION OF THE UPPER LIMB. 



Resting on the great pectoral muscle, it is nearly hemispherical I 

 in form, but most prominent at the inner and lower aspects. Its I 

 dimensions and weight vary greatly. In a breast not enlarged by 

 lactation, the width is commonly about four inches. Longitudinally 

 it extends from the third to the sixth or seventh rib, and trans- 

 versely from the side of the sternum to the axilla. Its thickness 

 is about one inch and a half. The weight of the mamma ranges 

 from six to eight ounces. 



Nearly in the centre of the gland (rather to the inner side) rises 

 the conical or cylindrical projection of the nipple or mamitta. 

 This prominence is about half an inch or rather more in length, is 

 slightly turned outwards, and presents in the centre a shallow 

 depression, where it is rather redder. Around the nipple is a 

 coloured ring the areola, about an inch in width, the tint of 

 which is influenced by the complexion of the body, and becomes 

 darker during pregnancy and lactation. The skin of the nipple 

 and areola is provided with numerous papillae and glands ; and on 

 the surface are some small tubercles marking the position of the 

 latter. 



In the male the mammary gland resembles that of the female in 

 general form, though it is much less developed ; and it possesM> u 

 small nipple, which is surrounded by an areola provided with hairs. 

 The glandular or secretory structure is imperfect. 



Structure. The mamma is a compound racemose gland, and 

 consists of small vesicles, which are united to form lobules and 

 lobes, and connected with each lobe is .an excretory or lactiferous 

 duct 



A layer of areolar tissue, containing masses of fat, surrounds the 

 gland, and penetrates into the interior, subdividing it into lobes ; 

 but between the lobules of the gland, and in the nipple and areola, 

 there is not any fatty substance. Some fibrous septa fix the gland 

 to the skin, and support it, being spoken of as the ligamenta sus- 

 pensoria of Astley Cooper. 



The ducts issuing from the several lobes (about twenty) are 

 named from their office galactophorous ; they converge to the areola, 

 where they swell into oblong dilatations or reservoirs (sinuses) of 

 one-sixth to one-third of an inch in width. Omvards from that 

 spot the ducts become narrower ; and, surrounded by areolar 

 tissue and vessels, they are continued through the nipple, nearly 

 parallel to one another, to open on the summit by apertures 

 smaller than the canals, and varying from the size of a bristle to 

 that of a common pin. 



Nipple. The substance of the nipple is composed in great part of 

 a network of interlacing bundles of plain muscular tissue, through 

 which the lactiferous ducts pass to the surface. Some of the 

 bundles extend from base to apex of the nipple ; and surrounding 

 the base is a set of circular fibres, with which radiating bundles 

 decussate. 



Arteries of JJlood-vessels. The arterics&re supplied by the axillary, internal mammary, 

 and intercostal, and enter both surfaces of the gland. The veins end 



form and 

 position ; 



with its 

 dimensions 



and weight. 



Position and 

 form of the 

 nipple : 



the areola 

 colour is 

 variable ; 

 skin has 

 glands. 



Breast or 

 the male. 



Structure. 



Investing 



and librous 

 tissue. 



Lactiferous 

 ducts ; 



open on end 

 of nipple. 



Muscular 

 tissue in 

 nipple. 



