Where does Bronchial veins drain ?

One casual question in my class led to this search for an anatomical mystery. When we were discussing  why left atrial oxygen saturation never reaches 100 % ? ,  it was attributed to desaturated  bronchial venous blood  draining  into pulmonary vein. How does this bronchial vein enter pulmonary venous circulation ? How many bronchial veins are there ? What  anatomical plane it runs   ? Surprisingly, even in this hi-tech era of academic excess, literature is sparse for this basic anatomical question. It is reported (In Greys anatomy ? ) Bronchial veins are two in number and both drain to Azygos and Hemiazygos veins (systemic) rather than pulmonary veins. So is our assumption wrong ? May not be.We realise these are only two visible and named bronchial veins .It is learnt they  probably carry only about 13 %  of bronchial  venous blood to systemic venous circuit. Image showing right and left bronchial veins draining to Azygos and hemiazygos veins.   It is assumed , remaining  87 % of  bronchial  venous blood drains to pulmonary  venous  circuit in an invisible  fashion (By unnamed twigs ?) desaturating  the LA blood by about one percent from 100 to 99 %. This is our current understanding. I haven’t come across any specific human  research that quantifies the bronchial venous channels and it saturation . It’s gratifying  to find one study specifically looked answer this question  in sheep study .(Charan H.B  et all Reference 1 )   True p...
Source: Dr.S.Venkatesan MD - Category: Cardiology Authors: Tags: Anatomy of heart Bronchail arterial and venous circulation bronchial arterial and venous circulation bronchial circulation bronchial vein rupture hemoptysis in mitral stenosis bronchial venous drainage clincial antomy research topics researc Source Type: blogs