AN INTERESTING ANOMALY IN THE PULMONARY 



VEINS OF MAN 



By W. C. George 

 Plates 30 and 31 



Anomalies in the venous system are so common that most of them 

 arouse no very great interest in the anatomist. One of the anomalies 

 (pi. 30, fio'. A) found last spring in the anatomical laboratory at 

 Chapel Hill and called to my attention by Dr. C. S. Mangum is so 

 unusual and of such embryological interest as to seem worthy of 

 a brief report. In this ca^e the blood from the upper left lobe 

 of the lung was drained not into the atrium but into the systemic 

 circulation. A fairly large vein, about one-half inch in diameter, 

 emerged from near the middle of the ventral surface of the upper left 

 lobe of the lung and coursed directly cephalad to empty into the left 

 innominate vein about two and one-half inches lateral to the union 

 of the two innominates to form the superior vena cava. The right 

 pulmonary veins and the pulmonary vein from the lower left lobe 

 communicate with the left atrium as usual. 



Somewhat similar connections between the veins of the pulmonary 

 and systemic circulations have been recorded previously. With ref- 

 erence to this sort of anomaly Bailey and Miller (1) make the state- 

 ment that "The upper (more cephalic) [pulmonary] vein on the right 

 side may open into the superior vena cava; or the upper vein on the 

 left side may open into the left innomonate vein. A possible explana- 

 tion of this is that the pulmonarj^ veins are formed after the heart 

 and other vessels have developed to a considerable degree, and some 

 of them may unite with the other vessels instead of with the atriiun. ' ' 

 This explanation is apparently based on an erroneous conception of 

 the pulmonary veins being sprouts that grow out from the sinus ven- 

 osus into the lungs, and does not seem to be a satisfactory explanation 

 in view of the relations existing between the pulmonary and bron- 

 chial veins in the adult and their embryonic origin as shown by Alfred 

 Brown (2). Brown has shown that the pulmonary system in the cat 

 arises from an indifferent splanchnic plexus in the region of the lung 

 bud (pi. 31, fig. C). This plexus communicates on the one hand 

 with the sinus venosus and on the other with the neighboring sys- 

 temic veins (cardinals, segmentals, et al.). This plexus around the lung 

 bud differentiates into two systems, the pulmonary and the bronchial. 

 In the adult the lungs receive their blood supply from two sources, 



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