THE ARTERIES 737 



(1) The inferior alveolar artery is large; branches from it emerge through four or 

 five mental foramina and take the place of the inferior labial. (2) The middle 

 meningeal artery enters th% cranial cavity through the foramen ovale and concurs 

 m the formation of the rete mirabile. (3) The buccinator artery is large and partly 

 compensates for the lack of a facial artery. It ramifies in the cheek and its fine 

 termmal branches extend to the lips. (4) The large infraorbital artery extends to 

 the snout and replaces the superior labial largely and the lateral nasal in part. The 

 malar branch compensates largely for the absence of the lateral and dorsal nasal 

 arteries. (5) The palatine artery is small. 



_ The superficial temporal artery ascends behind the temporo-mandibular 

 articulation and ramifies in the temporalis muscle; it is small and may be absent. 

 In the latter case the anterior auricular and transverse facial arteries arise separately 

 from the external carotid artery, which is directly continued by the internal maxil- 

 lary artery. 



The intercostal arteries number usually fourteen or fifteen on either side; of 

 these ten to twelve arise from the aorta, usually by short common trunks. Fre- 

 quently an intercostal artery is given off from that of an adjacent space. 



The bronchial and oesophageal arteries usually arise separately. 



The cceliac artery is half an inch to an inch long. It supplies a branch to the 

 left crus of the diaphragm, and divides into two primary branches, gastro-hepatic 

 and splenic. The gastro-hepatic artery is the larger. It gives off pancreatic 

 branches, the anterior gastric artery, branches to the lesser curvature of the stomach, 

 pyloric, and gastro-duodenal arteries. The latter divides into pancreatico-duo- 

 denal and right gastro-epiploic. The anterior gastric usually supplies the oesopha- 

 geal artery. The continuing trunk (A. hepatica propria) gives off a cystic branch 

 and divides in the portal fissure into three or four branches which ramify in the 

 liver. The splenic artery gives off the posterior gastric (usually), a branch to the 

 stomach above the cardia (A. divert! culi), twigs to the pancreas, short gastric 

 arteries to the left part of the great curvature, and splenic branches, and is con- 

 tinued as the left gastro-epiploic artery. 



The posterior gastric may arise from the gastro-hepatic or in the angle of divergence of the 

 two primary divisions of the coehac. The oesophageal branch may come from the posterior gas- 

 trio or the splenic. Other variations occur. 



The anterior mesenteric artery arises an inch or more behind the cceliac and 

 is long, like that of the ox. It gives twigs to the pancreas and is continued in the 

 mesentery as the artery of the small intestine or truncus intestinaUs. This gives off 

 about a dozen branches which form a series of arches along the mesenteric lymph 

 glands. From these is formed a rich network which gives off innumerable fine 

 branches placed close together. The ileo-cseco-colic artery gives off Ueal and caecal 

 arteries, and enters the axis of the spiral coil of the colon. Here it pursues a spiral 

 course and gives off branches which form remarkable plexuses; from the latter 

 numerous fine branches go to the centripetal coils. A short trunk gives origin to 

 right and middle colic branches. The right coUc artery is arranged like the colic 

 branch of the ileo-cseco-colic artery, with which it anastomoses at the apex of the 

 coil; it supplies the centrifugal parts of the coil. The middle colic artery goes to 

 the colon as it emerges from the coil and anastomoses with the posterior mesenteric 

 artery. 



A phrenico-abdominal artery arises on either side a little in front of the renal 

 arteries. It divides into branches which go to the costal part of the diaphragm 

 and the abdominal muscles. 



The renal and spermatic arteries present no special characters. 



The posterior mesenteric artery arises near the termination of the aorta. It 

 is small and is distributed like that of the ox. 

 47 



