^itANCHES OF AORTA IN THE CAVITY OF THE ABDOMEN. 283 



dorsal branch also proceeds a ramification, which enters the 

 spinal cavity, and is spent upon its membrane and upon the 

 medulla spinalis. 



After the Intercostals in their progress forward, have passed 

 beyond the middle of the ribs, they send off a branch, which 

 generally proceeds very near to the upper side of the lower rib. 

 The main trunk generally leaves the lower edge of the rib when 

 it has arrived within one-third of the length of the bone from 

 its anterior extremity. It then generally divides into several 

 branches, some of which are spent upon the pleura, and others 

 on the intercostal and the contiguous muscles. 



According to the situation of the different intercostals, some 

 of their ramifications, communicate with those of the internal 

 and external mammaries, of the phrenic, the lumbar, or the 

 epigastric arteries. 



PART 2. 



In the Cavity of the Abdomen. 



The Aorta passes into the cavity of the abdomen between 

 the crura of the diaphragm, as has been already mentioned. 

 In its course from the crura to its great bifurcation, it sends off 

 one pair of small arteries, called Phrenic, to the diaphragm. 

 Three single arteries, the Cceliac, the Superior and the Inferior 

 mesenteric, to the viscera of the abdomen. A pair of large 

 arteries, the EmuJgents, to the kidneys, with several that are 

 very small to their appendages ; as the Spermatics, Capsular, 

 the Ureteric, and the Adipose. In addition to these, there is 

 one pair of small arteries that go to the testicles in the male, or 

 to the ovaria and the uterus in the female, and four or five 

 pairs, called Lumbar Arteries, that go off laterally, like the in- 

 tercostals, to the parietes of the abdomen, and to the muscles 

 on the back, which are contiguous to them. 



