42 C. W. M. Poynter 



VEN.^ 



The venous anomalies have not attracted the same attention as 

 those of the arteries probably because of the apparently greater 

 physiological significance of the latter. The wide range in venous 

 pattern which may be called normal and the large number of 

 anastomosing trunks makes it difficult to recognize those conditions 

 which represent developmental irregularities. In satisfactorily ac- 

 counting for these anomalies the same detailed history of the 

 development is necessary which has been supplied in so many 

 regions for the arteries and which as yet is not available. It must 

 be kept in mind that the veins develop independently of the ar- 

 teries, Hochstetter (1891), Zumstein (1895). Vena cometes is a 

 secondary development and represents not only a late develop- 

 mental stage, but also the disappearance, in the majority of in- 

 stances, of the primary veins. 



VV. PULMONALES 



Brown (191 3) has shown in a 4.5 mm. embryo that the anterior 

 cardinal veins and the pulmonary veins are connected v^ith ari 

 indififerent capillary plexus. This fact undoubtedly accounts for 

 the irregular connections found between the vena cava and these 

 veins. 



The upper pulmonary vein may open into the right superior cava 

 or right atrium, Wilson (1798), Meckel (1820), Breschet (1819), 

 Otto (1830), Cooper (1836), Chassinat (1836), Lacroix (1844), 

 Taylor (1845), Lambl (i860). Foerster (1861), Duchek (1862), 

 Hickman (1869). Gruber (1876-85), Gegenbauer (1880), Crocker 

 (1879), Chiari (1880). Talini (1881), Toepley (1882), Chafifey 

 (1884). Epstein (1886), Rokitansky (1875), Hepburn (1886), 

 Miura (1889), Greenfield (1896), Shepherd (1890), Etlinger 

 (1891), Birmingham (1893), Patterson (1913), Griffith (1898), 

 Blondel (1901), Thiele (1903). Thane (1906), Strober (1908), 

 Looten (1910), Schroeder (1911). Merkel (1912). Brown (1913), 

 Gerard (1914), Niitzel (1914). 



The upper left pulmonary vein may open into the left innominate 

 or a persistent left cava. Johnston (i860). Blair (1901), Ingalls 

 (1907), Patterson (1913). Nuetzel (1914), Johnston (1914). 



