402 



ANGIOLOGY. 



right, passing out behind and between the pulmonary artery, and 

 the apex of the left auricular appendix, and immediately divides 

 into vertical and . transverse branches, with a distribution similar 

 to that of the right one. 



We will first consider the Posterior, afterwards the Anterior 

 Aorta. 



POSTERIOR AORTA. 



(PLATE V. 17.) 



The posterior aorta is larger and longer than the anterior. It 



FIG. 154. 



Thorax opened on the left side showing the heart and lai _e vessels in situ, a a, Pericardial sac , 

 b, Left ventricle ; c, Right ventricle ; d, Left coronary artery ; e, Primitive or common aorta ; e', 

 Anterior aorta ; e", Posterior aorta ; /, Pulmonary artery, divided and ligatured ; g, Anterior vena 

 cava ; h, Posterior vena cava ; i, Right bracial, or brachio-cephalic artery ; k, Left brachial artery ; 

 I, Left dorsal artery, giving off the subcostal posteriorly ; m, Left superior cervical artery ; n. Left 

 vertebral artery ; o, Left inferior cervical artery ; p, Left external ; and q, Internal thoracic arteries. 



commences at about the level of the fourth dorsal vertebra, 

 passes upwards and backwards, forming the aortic arch, and reach- 

 ing the left side of the spine at the sixth or seventh dorsal ver- 

 tebra. It passes straight backwards to the hiatus aorticus, entering 

 the abdomen between the pillars of the diaphragm, and terminat- 



