THE ARTERIES 627 



right one. The right longitudinal groove is placed far back and there is no pos- 

 terior sulcus. 



The Arteries 



The pulmonary vessels present no remarkable features. 



The aorta resembles that of the horse and ox in its course and relations, but the 

 arch is mure strongly curved. There is no common brachiocephalic trunk (anterior 

 aorta). 



The brachiocephalic artery arises first from the aortic arch and ]iasses forward 

 below the trachea to ihe tirst rib. Here it gives off the common carotid arteries, 

 and is continued around tiie first rib as the rigiit brachial. 



The superior cervical, vertebral, and dorsal arteries usually arise by a 

 common trunk. 



Thf inferior cervical artery is large; its ascending liranch gives off \hv posterior 

 thyroid artery and parotid branches. 



The internal and external thoracic arteries give branches to the pectoral 

 mammary glands; tin- external may be al)sent. 



The left brachial artery arises from the aortic arch just above the brachio- 

 cephalic. It curves forward and downward and turns around the anterior border 

 of the first rib. Its superior cervical, vertebral, and dorsal branches usually arise 

 separately. 



The carotid arteries arise from the brachioce])halic close together or by a very 

 short common trunk. They terminate in occipital and internal and external carotid 

 divisions. 



The occipital artery resembles that of the horse. 



The internal carotid artery usually arises by a common trunk with the occipital. 

 After giving off a large meningeal branch it passes through the foramen lacerum 

 and forms with the oj^iKJsite artery a rete mirabile which resembles that of the ox, 

 but is smaller and is not connected A\ith the vertebral and condyloid arteries. 



The external carotid artery has the same course and termination as in the horse. 

 Its branches jiresent the following special features; (1) The lingual artery is 

 relatively large and supplies the jiluiryngeal artery, the sul)lingual, muscular 

 branches, and branches to the soft palate, submaxillary gland, and larynx. (2) The 

 external maxillary artery is small and is distributed chiefly to the submaxillary 

 gland, the i)haryngeal lymph glands, the masseter and the panniculus. It does 

 not extend upon the lateral surface of the face. (3) The posterior auricular 

 artery is long and relatively larger it gives off the posterior meningeal. 



The internal maxillary artery pursues a flexuous course between the ramus of 

 the mandible and the pterygoid muscles. Its branches offer the following special 

 features; (1) The inferior alveolar (or dental) is large; branches from it emerge 

 through four or fivi» mental foramina and take the place of the inferior labial. 

 (2) The buccinator artery is also large and extends to the lips. (3) The infra- 

 orbital artery extends to the snout and replaces the superior labial largely and the 

 lateral nasal in part. The malar branch compensates largely for the absence of 

 the lateral and dorsal nasal. (4) The palatine artery is small. 



The intercostal arteries number fourteen to sixteen in either side; of these 

 ten to twelve arise from the aorta, usually by short common trunks. Freciuently 

 an intercostal artery is given off from that of an adjacent space. 



The bronchial and oesophageal arteries usually arise separately. 



The coeliac artery is half an inch to an inch long. It supplies a branch to the 

 left crus of the diaphragm and divides into two primary branches, gastro-hepatic 

 and splenic. The gastro-hepatic artery is the larger. It gives off pancreatic 

 branches, the anterior gastric arter^v, branches to the lesser curvature of the 

 stomach, pyloric and gastro-duodenal arteries. The latter divides into pancre- 



