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 branche?, with a distribution similar 

 to that of the right one. 



We will first consider the Posterior, afterwards the Anterior 

 Aorta. 



POSTERIOR AORTA, 

 f 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 large vessels in situ, a a, Pericardial sac't 

 b, Left Tentricle ; c, Eight ventricle ; d, Left coronary artery : e, Primitive or common aorta ; «', 

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

 cava ; h. Posterior vena cava ; i, Right bracial, or brachio-cephaUc 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 o,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 sjde of the spine at the sixth or seventh dorsal ver- 

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

 the abdomen between the pillara of the diaphragm, and terminal- 



