566 



DISEASES OF THE MAMMARY GLANDS. 



sinus, is extremely rich in elastic fibres, enabling the organ to undergo 

 great changes in volume without injury. 



Vessels. — The mammte are supplied by two great arteries, the 

 mammary arteries, which are given off from the prepubie arteries, pass 

 into the inguinal canal, and j^enetrate the gland by its upjDer, deep face. 

 Each principal lateral artery divides' into two trunks, one for the 

 anterior, the other for the posterior quarter. 



The veins which collect the blood from the mamm£e form two 

 Bj'stems, the first accompanying the mammary arteries, the second, 



more superficial, 



VM. — Its LE. " " 



VlvLa 



G-.P.M. 



giving rise to the 

 anterior sub- 

 abdominal mam- 

 mary veins. The 

 arter io-venous 

 plexus of the 

 udder, which re- 

 presents the vas- 

 cular pedicle of the 

 organ, penetrates 

 the gland, near a 

 line dividing the 

 posterior and 

 middle thirds of 

 the upper surface, 

 an inch or so in 

 front of the mam- 

 mary lymphatic 

 gland. 



Lymphatics.^ 



On either side of 



the middle line lies 



an extremely rich lymphatic plexus, the origin of which is to be found 



near the ends^ of the teats and in the peri-acinous spaces. 



The superficial collecting vessels are' dispersed under the skin, 

 perforate the fibrous sheath towards the base of the teat, and anastomose 

 with one another on the surface of the gland, the anastomosis being 

 most intimate between those of the same quarter, finally emptying 

 separately by two largo trunks into the retro-mammary lymphatic gland 

 of the same side. 



The vessels of the anterior quarter enter the lymphatic gland at 

 its most anterior point; those of the posterior quarter join it a little 

 below. 



Fig. 237. — Schema showing the structure and organisation of 

 the udder. Antero-posterior section showing the arrange- 

 ment of the anterior and posterior quarters and the teats, 

 skin, transverse partition, etc. GEM, Retro-mammary 

 Ij'mph gland; L^;, lymphatics of the posterior quarter; 

 Lrt, lymphatics of tlie anterior quarter ; LE, efferent lym- 

 phatics ; AM, mammary artery ; VM, mammary vein ; 

 VMa, anterior mammary vein (subcutaneous abdominal 

 vein) ; C, transverse inter-mammary septum. 



