Congenital Anomalies of the Heart 21 



It is sometimes impossible to tell in a given case whether the 

 defect is of the septum primum or secundum ; in general, how- 

 ever, it may be said that lesions of the septum primum are located 

 on the lower or posterior part of the atrial septum, while those 

 of the fossa ovalis and upper part of the septum are defects of 

 the septum secundum. 



Lacroix (1844), Bednar (1852), Smith (1880), Hopkins (i88g), Preisz 

 (1890) 3 cases, Hawkins (1891), Ruge (1891) 2 cases, Burke (1902), 

 Dhotel (1902), Wright & Drake (1903), Ebbinghaus (1904), Soldner 

 (1904), Ingalls (1907), Abbott (1910), Morrison (1912), Lusenbacher 

 (1916). Nineteen cases. 



3. Anomalies of the Septum Secundum 



(a) Open Foramen Ovale. — A patent foramen ovale is so fre- 

 quently encountered that it should not be considered as an anom- 

 aly. In our dissecting rooms the foramen has been found patent 

 in 25 per cent, of the subjects if we consider any condition in 

 which a probe will pass as patency. Bizot (1837) found the 

 foramen patent in 13 per cent, of cases in adults and Adami in 

 14.5 per cent of 1,374 autopsies. Peacock (1852) explained the 

 closure of the foramen showing that the shifting of the cornua 

 and the drawing up of the valve about the margin of the opening 

 produces a physiological closure even when the finger can be 

 thrust through and the valve so displaced. The fact that an ad- 

 hesion had iiot formed between the septum and the valve he did 

 not Qonsider as an anomaly. On the other hand, those cases, so 

 frequently described, in which the foramen is sufficiently open 

 to admit a finger, must be considered as anomalous. The condi- 

 tion of fully open foramen ovale was recognized as an anomaly 

 by Peneau in 1598. 



All degrees of failure of closure of the foramen may be seen, 

 but this group consists largely of cases in which there is an ab- 

 sence of the septum ovale. Cases in which the septum contains 

 so many openings as to be spoken of as " cribif orm " are included 

 in this list. Twenty per cent, of all cases present no other devel- 

 opmental defect. The condition represents 70 per cent, of all 

 atrial septum defects and is encountered in 23 per cent, of all 

 hearts studied. 



