194 AORTA. 



intercostal muscles, towards the junction of the diaphragm opposite Jthe junction of the last 



rib with its cartilage, where it descends from dorsal and first abdominal vertebra, having the 



the rib towards the middle of the intercostal renal capsules and semilunar ganglia on either 



space, and there anastomoses with the anterior side of it, with the lobulus Spigelii to the right, 



intercostal arteries sent off from the internal the cardiac orifice of the stomach to the left, 



mammary. Besides supplying the intercostal the superior border of the pancreas inferiorly, 



muscles, pleura, and ribs, the intercostal arteries and the stomach and lesser omentum in front : 



give several branches, which pierce the external it is closely embraced by branches of the solar 



layer of intercostal muscles, and carry blood plexus. 



to the muscles and integuments covering the The creliac artery, which is often scarcely 



thorax. The lower intercostalsalso send branches half an inch in length, immediately divides into 



to the abdominal muscles, diaphragm, and three branches, the gastric or coronaria superior 



quadratus lumborum, which freely anastomose ventriculi, the hepatic, and the splenic, which 



with the internal mammary , epigastric, phrenic, constitute the tripod of Haller. Sometimes the 



lumbar, and circumflex iliac arteries. cosliac axis gives off the phrenic and superior 



Anastomoses. The intercostal arteries have capsular. 



a chain of anastomoses with each other by Coronary artery of the stomach. The coro- 

 communicating branches which cross the heads nary artery is the smallest of the three branches 

 of the ribs. By this means the superior freely furnished by the trunk of the creliac ; it some- 

 communicate with the subclavian by its inter- times arises from the aorta itself. Passing 

 costal artery. Inferiorly, their anastomosis upwards, forwards, and to the left, it arrives 

 with the phrenic, circumflex ilii, and lumbar at the cardiac orifice of the stomach, from 

 arteries, is equally free ; internally they anasto- which it proceeds forwards and to the right, 

 mose with the arteries of the spinal cord, and following the direction of the lesser arch of 

 in front with the internal mammary and epi- the stomach until it arrives near the pylorus, 

 gastric. where it anastomoses with the pyloric branch 

 III. Branches of the abdominal aorta. of the hepatic. When the coronary artery has 

 They may be divided into anterior and lateral, arrived at the cardiac orifice of the stomach, it 

 The anterior branches are, the inferior phrenic, sends one or more branches upwards along the 

 ccBliac, superior and inferior mesenteric. ossophagus which supply that part with blood, 

 Phrenic arteries. The phrenic arteries are and anastomose with the cesophageal arteries 

 two in number; they arise from the aorta im- from the thoracic aorta : it then sends branches 

 mediately after its entrance into the abdomen, round the cardiac orifice, which nearly encircle 

 generally distinct, sometimes from a common that part, and ramify over the great extremity of 

 trunk, and occasionally one or both arise from the stomach, where they anastomose with the vasa 

 the cceliac artery, or one of its branches. Each brevia of the splenic. In its course along the 

 phrenic artery passes outwards in front of the lesser arch of the stomach the coronary sends 

 cms of the diaphragm, and along the upper many branches over both surfaces of that viscus, 

 edge of the renal capsule of its own side. The which anastomose with each other and with 

 right artery passes behind the vena cava, and the right and left gastro-epiploic. The ter- 

 the left behind the oesophagus. They run on minal branch of the coronary which ends at 

 the abdominal surface of the diaphragm, and the pylorus is sometimes called superior pyloric. 

 at the posterior edge of the cordiform tendon Sometimes the coronary artery gives off the 

 each vessel divides into an external and an right hepatic immediately before reaching the 

 anterior branch. The external branch supplies cardiac orifice of the stomach, 

 the fleshy substance of the ala of the diaphragm, The hepatic artery passes forwards and to 

 and sends several branches towards the external the right under the lobulus Spigelii to the neck 

 attachments of that muscle which anastomose of the gall-bladder. In this part of its course 

 with the lower intercostal and lumbar arteries ; it gives a few twigs to the gastro-hepatic omen- 

 while the anterior branch, coursing round the turn and the inferior surface of the liver; when 

 margin of the cordiform tendon, supplies the it reaches the pylorus, it gives two considerable 

 anterior part of the diaphragm, and anastomoses branches called the pyloric and the right gastro- 

 with its fellow of the opposite side, behind the epiploic. The pyloric passes from right to left 

 ensiform cartilage, sending forwards branches along the lesser arch of the stomach, where it 

 to anastomose with the internal mammary. meets the coronary with which it anastomoses, 

 Minute branches are given oft by the phrenic sending several branches over the anterior and 

 arteries near their origins to the semilunar posterior surfaces of the stomach to anastomose 

 ganglia and renal capsules : a small twig from with the right gastro-epiploic artery. The right 

 the right phrenic ascends along the vena cava gastro-epiploic artery, much larger than the 

 through the diaphragm to anastomose with the pyloric, arises after that vessel ; it passes down- 

 comes nervi phrenici of the internal mammary, wards behind the pylorus, and arrives at the 

 Another similar twig, given to the esophagus greater arch of the stomach, along which it 

 by the left phrenic, while passing behind that courses from right to left and anastomoses 

 tube, anastomoses with the middle cesophageal with the left gastro-epiploic. While passing 

 arteries. behind the pylorus, it gives several branches to 

 The cceliac artery, called, also, cceliac axis, the pancreas and duodenum, one of which, 

 is one of the largest and shortest of the vessels somewhat larger than the rest, called pancreatico- 

 given off by the abdominal aorta. It generally duodenalis, lies concealed between the duo- 

 arises from the aorta, between the crura of the denum and head of the pancreas, and anasto- 



