VEINS OF THE HEAD AND NECK. 255 



1. The Inferior Thyroid Vein (Vena Thyroidea Inferior) 

 arises from the inferior part of the thyroid gland, by many 

 small roots, which anastomose with those of the opposite side. 

 It descends in front of the trachea, involved in the loose cellu- 

 lar and fatty matter lying upon it, and empties itself iMo the 

 left brachio-cephalic vein, or Transverse Vein. 



There is occasionally another thyroid vein, called the mid- 

 dle, which discharges itself into the lower part of the internal 

 jugular, 



2. The Vertebral Vein (Vena Vertebralis) is placed in the 

 same canal with the vertebral artery. At its upper extremity 

 it anastomoses with the occipital sinus, by a branch lodged in 

 the posterior condyloid foramen. In its descent of the canal of 

 the transverse processes, it communicates at each intervertebfal 

 foramen with the vertebral sinuses, and also receives a branch 

 from the muscles of the neck. It issues at the sixth transverse 

 .process, and going on the right side behind the subclavian ar- 

 tery, but on the left, in front of it, it is, final \y, emptied into the 

 commencement of the vena innominata. 



3. The Superior Intercostal Vein (Vena Intercostalis Supe- 

 rior) is on the right side an inconsiderable trunk, sometimes 

 deficient, which commences by branches belonging to the two 

 first intercostal spaces, and empties into the vena innominata 

 just below the vertebral On the left side it is much larger, 

 and arises from the six or eight superior intercostal spaces. It 

 lies on the left side of the bodies of the upper dorsal vertebra, 

 and at each intercostal space, as it ascends, receives its contri- 

 bution of an intercostal vein, corresponding with the intercostal 

 artery; it also receives branches from the oesophagus, and about 

 the third dorsal vertebra the left bronchial vein is discharged 

 into it. Issuing from the thorax above, it discharges into the 

 left vena innominata near its commencement. 



4. The Internal Mammary Vein (Vena Mammaria Jnterna) 

 arises from the terminating branches of the internal mammary 

 artery, and in its situation and course corresponds wilb the lat- 

 ter. It is re-enforced by small branches from the diaphragm, 

 the pericardium, and the thymus gland. Each internal mam- 



