INTERNAL MAMMARY ARTERY. 



375 



Those placed nearest to the mammary gland supply that organ, and in the female 

 they are of comparatively large size, especially during lactation. Some offsets ramify 

 on the sternum. 



Fig. 265. 



Fig. 265. DISSECTION OF THE RIGHT SIDE 



OF THE ANTERIOR THORACIC AND AB- 

 DOMINAL WALL, TO SHOW THE ANASTO- 

 MOSES OF THE INTERNAL MAMMARY, 

 INTERCOSTAL, AND EPIGASTRIC VESSELS 

 (slightly altered from Tiedemann). 



The pectoral part of the serratus mag- 

 nus, the external aud internal ob- 

 lique, and the rectus abdoninis muscles, 

 have been removed ; 1, upon the subclavius 

 muscle, points to the first part of the 

 axillary artery above the pectoralis minor 

 muscle, giving rise to the acromio-thoracic 

 artery, which is cut short ; 2, upon the 

 pectoralis minor, points to the lower part 

 of the axillary artery and vein ; 3, the 

 long thoracic artery ; 4, on the cartilage of 

 the first rib, marks the upper part of the 

 internal mammary artery ; 4', the lower 

 part of the same artery giving its abdominal 

 branch behind the cartilage of the seventh 

 rib ; 5, in the fourth intercostal space, 

 marks the anastomosis of the internal 

 mammary and intercostal arteries ; 6, 

 anterior branches of the internal mam- 

 mary artery ramifying over the front of the 

 sternum ; 7, on the trans versalis muscle 

 immediately above the internal inguinal 

 aperture, points to the last part of the ex- 

 ternal iliac artery, from which are seen 

 rising, 8, the deep epigastric artery, and 

 9, the deep circumflex iliac ; 10, the anas- 

 tomosis of the epigastric with the abdomi- 

 nal branch of the internal mammary 

 artery ; 11, the spermatic cord and sper- 

 matic twig of the epigastric artery ; 12, 

 the femoral artery giving small twigs to 

 the groin and the superficial pudic vessels ; 

 13, the femoral vein; 14, a lymphatic 

 gland closing the femoral ring. 



(e) The musculo-plirenic artery, the 

 outer of the two branches into which the 

 internal mammary artery divides, in- 

 clines downwards and outwards behind 

 the cartilages of the false ribs, perforating 

 the attachment of the diaphragm at the 

 eighth or ninth rib, and becoming gra- 

 dually reduced in size as it reaches the 

 last intercostal space. It gives branches 

 backwards into the diaphragm; others, 

 which pass outwards to form the anterior 

 intercostals of each space, and are dis- 

 posed precisely like those which are derived higher up from the main internal mam 

 mary ; and some which descend into the abdominal muscles. 



(/) The abdominal branch or superior epigastric artery of the internal mammary, 

 descending into the wall of the abdomen, lies behind the rectus, between the muscle 

 and its sheath ; and afterwards, entering the muscle, terminates in its substance, at 



