174 



Anatomy of the Rabbit. 



(4) The a. intercostalis suprema passes backward to the internal 

 surface of the thoracic wall, giving off the first three inter- 

 costal arteries in the intercostal spaces, and also small 

 branches to the oesophagus and trachea. 



(5) The internal mammary artery (a. mammaria interna), the 

 first portion of which has been removed with the ventral 

 wall of the thorax, passes backward to the ventral abdominal 

 wall as the superior epigastric artery (a. epigastrica superior) 

 anastomosing with the inferior epigastric (p. 115). 



(b) The superior caval vein (v. cava superior) is formed at the 

 base of the neck by the union of the internal and external 

 jugular veins, the latter vessel receiving at this point the 

 subclavian vein (v. subclavia). The right superior caval 

 passes almost directly 



backward, crossing the 

 ventral surface of the 

 right subclavian artery, 

 and enters the anterior 

 portion of the right 

 atrium. The left vessel 

 crosses both the left 

 subclavian artery and 

 the arch of the aorta, 

 reaching the right at- 

 rium from the dorsal 

 surface of the heart. 



(c) The vagus nerve. On 

 the right side the nerve 

 crosses the ventral sur- 

 face of the subclavian 

 artery, passing dorsad 

 to the wall of the oeso- 

 phagus. It gives off 

 the recurrent nerve 

 (n. recurrens), the latter 

 curving around the sub- 

 clavian artery and 

 passing forward along 

 the side of the trachea 

 to the larynx. On the 

 left side the vagus 

 passes between the arch of the aorta and the base of the 

 heart to the ventrolateral wall of the oesophagus. The recur- 

 rent nerve passes forward on the dorsal side of the arch. 



(d) The ramus cardiacus of the vagus. In front of the subclavian 

 artery the nerve is at first closely associated with the vagus 

 trunk, lying on its medial side. On the right side it passes 

 to the dorsal surface of the subclavian- and on the left to the 



Fig. 52. Plan of the venous and lymphatic 

 trunks of the anterior portion of the body. 

 After McClure and Silvester. 



a., azygos vein; ao.. aorta; c.s., left superior 

 caval vein; d.th., thoracic duct; j.e., j.i., and 

 j.tr., external, internal, and transverse jugular 

 veins; s., left subclavian vein; tr.s., transverse 

 scapular vein. 



