Congenital Anomalies of Arteries and Veins 5 



comparative value. From my own measurements I am sure that 

 such length differences M^ill fall into a simple probability curve. 

 Anatomists have generally used some arbitrary point as a vertebra 

 or laryngeal cartilage to represent the point of division; Ouain 

 (1844) reported division at the cricoid cartilage 5 times in 295; 

 I have recorded such division twice on the left and once on the 

 right. Others reporting short trunks are Morgagni (1761), Burns 

 (1809), Ryan (1812), Monro (1825), Otto (1830), Hart (1836), 

 Hyrtl (1841), Dubrueil (1847), Nuhn (1849), Schwegel (1859), 

 Potherat (1889), Kantor (1905), Orr (1906). A delay in divi- 

 sion, making a long trunk, represents the other extreme ; Quain 

 found 10 in 295 in which the bifurcation was opposite the hyoid 

 bone; I have found 18 such divisions and many others nearly as 

 high; see also Demarquav (1845) and Reinhardt (1850), Boulard 



(1857)- 



A. Car Otis Externa and Branches 



The external carotid may run lateral to the stylo-hyoid muscle, 

 Quain (1844), Gruber (1876); I have twice encountered this 

 variation. 



The trunk may be lacking in that all of the branches spring from 

 a common point, apparently the common carotid, Huber (1777), 

 Burns ( 1809) , Langenbeck ( 1822) , Hyrtl ( 1841 ) , Dubrueil ( 1847) , 

 Deaver (1888), Bellini (1894), Anderson (1889), Descomps 

 (1910). 



The general arrangement of its branches is much more constant 

 than of the subclavian, but the variations have attracted much more 

 attention, as indicated by the large number of anomalies reported. 

 The number of branches varies; Livini (1903) thinks 9 the normal 

 number, but this represents only an arbitrary number of individual 

 rami and not a constant group, which occurs in only about 50 per 

 cent. I am sure there is no advantage in attempting to average 

 types of branching, for all variations tend to be individual. 



A. Thyreoidea Superior 

 I agree with Livini in finding it present in 100 per cent. ; Labatt 

 (1837) reported its absence. It is occasionally double, Tiedemann 

 (1822), Lauth (1833), Quain 3:292, Gruber (1859), Anderson 

 (1879), Bard (1875). 



