THE PULMONAEY AETEEY. 



883 



the lung it gives off numerous branches which correspond with and accompany the 

 dorsal, ventral, and accessory branches of the right bronchus (see p. 1097). 



The left branch of the pulmonary artery, shorter, smaller, and somewhat 

 higher in position than the right, passes laterally and posteriorly from the bifurca- 



34 



IG. 757. THE PULMONARY ARTERIES AND VEINS AND THEIR KELATIONS IN A FORMA LTN- 

 HARDENED PREPARATION. 



The ascending aorta and part of the superior vena cava have been removed. 



1. Aorta. 



2. Superior vena cava. 



3. Upper right pulmonary 



vein. 

 I. Right pulmonary artery. 



5. Superior vena cava. 



6. Left innominate vein. 



7. Innominate artery. 

 Right innominate vein. 



9. Subclavius muscle. 

 10. Clavicle. 



11. Internal mammary artery. 



12. Subclavian vein. 



13. Transverse scapular artery. 



14. Transverse cervical artery. 



15. Vertebral artery. 



16. Inferior thyreoid artery. 



17. Internal jugular vein. 



18. Common carotid artery. 



19. Superior thyreoid artery. 



20. Sterno-thyreoid muscle. 



21. Omo-hyoid muscle. 



22. Sterno-hyoid muscle. 



23. Platysma. 



24. Sterno-hyoid muscle. 



25. Sterno-thyreoid muscle. 



26. Sterno-mastoid muscle. 



27. Phrenic nerve. 



28. Vagus nerve. 



29. Vertebral artery. 



30. Inferior thyreoid artery. 



31. Thoracic duct. 



32. Left subclavian artery. 



33. Subclavius muscle. 



34. 1st rib. 



35. Left common carotid 



artery. 



36. Aorta. 



37. Ligamentum arteriosum. 



38. Left pulmonary artery. 



39. Upper left pulmonary 



vein. 



40. Pulmonary artery. 



tion of the pulmonary stem, and runs, in the root, to the hilum of the left lung ; it 

 then descends, in company with the main bronchus, to the lower end of the lung. 



Relations. Before it enters the lung it is crossed, anteriorly, by the upper left 

 pulmonary vein ; posterior to it, are the left bronchus and the descending aorta ; above, are 



