CIRCULATORY SVSTEIM. 179 



The Middle Sacral issues at the Bifurcation of the Trunk, 

 r Circumflex of the Ileum 

 Fv^Pl•n^^I IllnrJ Artery of the Chord f Branch to the Groin 



£-xteindi ijiac^ Arteria Profunda \ Epigastric <^ Branch to the Ring 

 iFemoral L Ext. Pudic 



Inguinal 



Muscular Branches 

 Stifle ditto 

 Muscular ditto 

 Popliteal -{ Recurrent 



r Recurrent Articular 

 Anterior Tibial. . . . VV"scular Branches 

 \ L-utaneous ditto 

 / IMetatarsal Branches r Recurrent 

 ^Metatarsal Artery . . \ Ext. Plantar 

 rlMuscular Branches lint, ditto 

 J Medullary 

 ■ I Tarsal 

 Lint. Metatarsal <{ Recurrent. 



Femoral 



^Posterior Tibia 



THE AORTA, the main trunk of the general arterial system, 

 takes its origin out of the base of the left ventricle of the heart, 

 and mounts upward between the left auricle and the pulmonary- 

 artery ; the latter vessel by inclining forward leaving visible, on a 

 side view, a small angular portion of the aorta. The length of 

 the single trunk measures about two inches. It is situated di- 

 rectly underneath the fourth dorsal vertebra, where its bifurcation 

 takes place into miterior and posterior aorta; vessels that are 

 both of them curved in their course, but of unequal dimensions. 



The coronary arteries are the only branches given off 

 from the single trunk : they arise close to its root, immediately 

 above the semilunar valves. The right coronary artery emerges 

 from the interspace between the pulmonary artery and the right 

 auricle, winds round the fissure separating that cavity from the 

 right ventricle, and turns down under the termination of the vena 

 cava, within the furrow dividing the ventricles, upon the side of 

 the heart, distributing lateral ramifications in its course which 

 penetrate the substance of the parietes, and ending in small 

 spiral branches near the apex cordis. The left coronary artery, 

 in passing out between the pulmonary artery and left auricle, 

 sends off a large branch which encircles the other auriculo-ven- 

 tricular fissure ; it then takes its course downward within the 

 ventricular furrow upon the left surface of the heart, distributing- 

 lateral branches which supply the parieties forming this side, and 

 ending in spiral ramifications which extend quite around the apex 

 cordis, and anastomose with those \\\)0\\ the opposite side. 



