Congenital Anomalies of the Heart 19 



(1889), Preisz (1890) 4 cases, Variot et Gampert (1890), Rolleston (1891), 

 Steven (1892), Geipel (1892), Meslay (1895), Eisenmenger (1897), 

 (1898), Griffith (1899), Spalverini et Barbieri (1902), Amenville (1905), 

 Rogers & Fortiscue (1905), Carpenter (1909), Erdmenger (1912), Griffith 

 (1915). 



(b) Ventricular septum defective in pars memhranacea: Loschner & 

 Lambl (i860) 2 cases, Crocker (1878) (1879), Stone (1881), Toennies 

 (1884), Willcocks (1886), Pryor (1889), Stadler (1891), Passow (1894), 

 Rheiner (1896), Freyberger (1898), Spalverini & Barbieri (1902), Cowan 

 (1903), Carpenter (1908), Bissell (1913), Heller & Gruber (1914), Morse 

 (1915), Parrura (1916). 



(c) Other Defects of the Interventricular Septum. — Defects 

 in other portions of the septum than the base are very unusual. 

 The cases are generally of multiple openings and may be at any 

 point in the body of the septum. The condition no doubt repre- 

 sents a growth disturbance which was of short duration or suffi- 

 ciently slight to permit the final normal developmental stages. 

 Interesting cases have been reported by : 



Chiari (1881), Toennies (1884), Griffith (1897), Chessman (1905), and 

 Robertson (1911). 



§ VIII. ANOMALIES OF THE INTERATRIAL SEPTUM 



The atrial septum presents, through its complexities of devel- 

 opment, several problems which must be considered in inter- 

 preting and classifying ano'malies. The cavity of the primitive 

 atrium is divided to form two chambers by a septum which is 

 known as the septum primum. This septum grows downward 

 into the cavity until it unites with the endocardial cushions. Be- 

 fore this union is complete the lower border of the septum is free 

 and the atria communicate below it by an opening which is known 

 as the ostium primum. About the time that the division of the 

 chambers is complete an opening appears in the septum primum 

 which is the foramen ovale. A second septum, the septum secun- 

 dum, grows downward to the right of the septum primum and 

 some time after birth closes the foramen ovale. 



This study indicates that developmental disturbances of the 

 interatrial septum are slightly more than half as frequent as 

 those of the interventricular septum. Some defect of the atrial 



