Page:Encyclopædia Britannica, first edition - Volume I, A-B.pdf/277

 Part III. A N A T O M Y. 233 branches called arterhe cyjiicee; and another named 6>/a- As they approach the inteftines, all thefe branches communicate, firft by reciprocal arches; then by ariolae ria, which is»loft in the great lobe of the liver. Afterwards, this artery enters the filfure of the liver, and malhes of all kinds of figures; from which is deand joins the vena portfe, with which it runs within a tached an infinite number of finall ramifications, which membranous vagina, called capfula Glijfom, and accom- furround the inteftinal canal, like an annular piece of netpanies it through the whole fubftance of the liver by nu- work. merous ramifications, which may be termed arterice he- The firft branches from the convex fide of the mefenteric arch, which are very fhort, fupply the pancreas and patic# propria. Before it enters the liver, it gives fmall branches to mefocolon, and communicate with the duodenal artery. the external membrane of this vifcus, and to the capfula The laft branches go to the appendicula vermiformis, and fend a portion of an arch to the beginning of the Glilfoni. Immediately after the origin of the fplenic artery from colon. the cseliaca, it runs toward the left hand, under the fto- The confiderable branches from the concave fide of the raach and pancreas, to the fpleen. It adheres clofely to mefenteric arch, are feldom above two or three in numthe pofterior part of the lower fide of the pancreas, to ber ; but before they arife, a fmall ramus goes out to which it gives feveral branches, named arteriapancreatic#. the duodenum, and gives fome very fmall arteries to the Near the extremity of the pancreas, under the left pancreas. portion of the ftomach, the fplenic artery gives off a The firft confiderable branch from the concave fide of principal branch, called gajlrica fmijlra or minor, the arch goes into the mefocolon towards the right porwhich runs from left to right along the left portion of tion of the colon. the great curvature of the ftomach, giving branches to The fecond principal branch, having run for fome fpace both fides of this portion, which communicate with thofe through the mefentery, divides into three rami; the firft of which goes to the lower part of the right portion of of the coronaria ventriculi. This gaftric artery fends likewife another branch at the colon, the fecond goes to the beginning of the colon lead: to the extremity of the pancreas, which commu- and inteftinum caecum. nicates with the other pancreatic arteries. It alfo fup- The third ramus of the fecond branch, having complies the omentum with branches, termed gajlro-epi- municated with the fecond, gives fmall twigs to the caeploic#ftnijlr#; and then it communicates with the right cum, appendicula vermiformis, and extremity of the gaftrica; and from this union, the gaftro-epiploicae mediae ileum. The lower mefenteric artery goes out anteriorly from are produced. Afterwards, the fplenic artery advances towards the the aorta defeendens inferior, about a fingers breadth fpleen, in a courfe more or lefs contorted; but before it or more above the bifurcation, and below the fpermatic arrives at that vifcus, it gives two or three branches to arteries; and having run about the length of an inch, the large extremity of the ftomach, commonly called or fomething more, it is divided into three or four vafa brevia ; and one to the omentum, named epiploica. branches. At the fpleen, this artery divides into four or five The firft: or fuperior branch, about an inch from its branches, which enter that vifcus, after having given origin, divides into two rami; the firft of which runs I fome fmall twigs to the neighbouring parts of the fto- along the left portion of the colon. The fecond ramus having communicated with the firft, runs down upon the mach and omentum. The fuperior mefenteric artery arifes anteriorly from fame portion of the colon. the lower portion of the defeending aorta, a very little The middle branch divides into two rami; one of Vyay below the casliaca, going out a little .towards the which pafles upward on the extremity of the colon, comright hand, but bending immediately afterwards to the municating by arches with the fecond ramus of the fuperior branch; the other runs down on the extremity of left. , Near its origin, it gives off a fmalh branch, which the fame inteftine. dividing into two, goes to the lower fide of the head of The lower branch goes to the fecond portion of the the pancreas, and neighbouring part of the duodenum, colon, or to both. communicating with the inteftinalis by fmall arches, and It fends another confiderable branch downward, called arteria hamorrhoidalis interna, which runs down behind areolae or maflies. _ Afterwards it paffes over the duodenum, between this the inteftinum redtum, to which it is diftributed by feinteftine and the meferaic vein, between the two laminae veral ramifications. of the mefentery; and then bending in an oblique direc- The renal arteries, commonly called emulgents, are tion from left to right, and from above downward, by ordinarily two in number, and go out laterally from the very fmall degrees, it advances toward the extremity of inferior defeending aorta, immediately under the mefenthe ileum. By this incurvation, it forms a kind of long terica fuperior, one to the right hand, the other to the arch, from the convex fide of which a great many left. branches go out. They run commonly without divifion, and almoft horiThefe branches are fixteen or eighteen in number, or zontally to the kidneys, into the depreffions of which thereabouts, and almoft all of them are beftowed on the they enter by feveral branches, which form arches in the fmall inteftines, from the lower third part of the duo- inner fubftance of thefe vifeera. denum to the caecum and colon. From thefe arches, numerous fmall rami go out toVox. I. No. 10. 3 3N ward I