Congenital Anomalies of Arteries and Veins 13 



Many of the studies of the circulation of the brain have been 

 made on defectives and insane and all of these investigators have 

 seemed to hold the idea that some subtile connection exists between 

 arterial anomalies and defective brain function. The quoted per- 

 centages of variations can hardly be taken at face value because 

 the standard for computation is more nearly some ideal text figure 

 than the condition found in 100 supposedly normal individuals. 

 Barbieri (1868) found 15 per cent, anomalies in 1,145 brains of 

 idiots. Fregerio found 21 vascular anomalies in 37 insane, and 

 Blackburn (1907) 155 of 250 insane with such anomalies, while 

 Longo (1905) found 29 anomalies in 50 supposedly normal brains. 

 A very excellent piece of work was done by Mori (1893), who 

 found 32 examples of vascular anomalies in 350 insane; this agrees 

 with Windle (1887), who studied 200 cadavers and found that 

 wide latitude should be employed in determining the normal. 

 More recently Fawcett and Blackford (1905) examined 700 speci- 

 mens. 



A. Subclavia and Its Brandies 



I have previously, '16, p. 41, discussed the origin of this artery, 

 so now need only consider the course and branches. The course 

 and relations show very little variation, except that the vessel may 

 be carried upward by a cervical rib, Adams (1839), Halbertsma 

 (1856), Fischer (1858), or the relation to the scalenus anticus may 

 be disturbed; it may perforate the muscle, Knox (1843), Quain 

 (1844), Wood (1867) ; it may form a ring around the muscle. 

 Beck (1846), Hyrtl (1853), Schwegel (1859) 3: 140; the latter I 

 have observed three times. It may pass in front of the muscle, a 

 condition I have observed only once, but which is generally more 

 frequent, Manec (1832), Lizars (1834), Hird (1837), Velpeau 

 (1839), Demeaux (1841), Cruveilhier (1852), Beck (1846), 

 Duval (1853) .5 per cent., Schwegel (1859) .3 per cent., Luschka 

 (1862), Bochdalek (1867), Romiti (1905). 



Papers by Bean (1904) and Pellegrini (1906) represent the 

 most extensive recent work on the subclavian. The former at- 

 tempts to reduce his data to types which, with variables of this 

 nature, must not only be unsatisfactory, but misleading, in that it 

 suggests sharp definition between variations instead of the gradual 



