148 EQUINE ANATOMY, 



enteen in number. Thirteen are from the thoracic por- 

 tion of the posterior aorta, the iirst from the cervical 

 artery, and the three following from the subcostal (see 

 page 145) ; they run through the intercostal space and 

 divide into a superior or dorso-spinal artery, an ascend- 

 ing branch going to the muscles of the dorsal region ; 

 and an inferior, intercostal proper, or descending 

 branch running along the posterior border of tlie rib 

 downwards to anastomose with branches of the inter- 

 nal thoracic, of the anterior and posterior abdominal 

 and even circumflex iliac arteries. The intercostal ar- 

 teries form the parietal branches of the thoracic 

 aorta. 



2. Broncho- (ESOPHAGEAL. — Visceral branch of the 

 thoracic aorta, rises from the convexity of the arch 

 of the aorta and near the bifurcation of the trachea, 

 gives off the two bronchial arteries ramifying with the 

 bronchia ; and the oesophageal, divided into superior 

 and inferior, which run above and below the oesophagus 

 backwards to anastomose with branches of tlie gastric. 



3. Diaphragmatic — See description of diaphrag- 

 matic region, page 151. 



Abdominal collateral. — See description of the ab- 

 dominal cavity, page 59. 



Terminal branches. — See arteries of the hind ex- 

 tremity and pelvic cavity, pages 59 and 151. 



