A CASE OF CYCLOPIA 



201 



Vascular anomalies 



As has been already noted, the left internal carotid artery 

 within the skull was reduced to a mere thread-like vessel. Exam- 

 ination also showed that the left carotid canal was proportionately 

 reduced. The right internal carotid is somewhat larger than 

 normal, as might be expected. .In examining the origin of these 

 vessels in the neck region it was found that the relations on the 

 right side were normal. On the left side the internal carotid 

 was so much reduced as to be distinguished only with difficulty. 

 It arises from the posterior aspect of the common carotid at 

 about the level of origin of the lingual artery. The left facial 

 artery is somewhat larger than the right (diagram, fig. 6). 



1\ 



■^^%.:fSJ 



' A.o.e. 



Fig. 6 Diagram of arrangement of arteries jn neck region. A.c.e., external 

 carotid artery; A.c.i., internal carotid artery; A.f., facial artery; A.I., lingual 

 artery; A.o., occipital artery; A.t.s., superior thyroid artery; Md., lower jaw; Tr., 

 trachea. 



The course of the internal carotid arteries within the skull 

 to the point where a single median vessel pierces the dura, has 

 already been described. 



Encephalic arteries. The vessels of this region are represented 

 in figure 7 as pinned out and seen from above. Postreiorly 

 the two vertebral arteries unite in a normal fashion to form the 

 main basilar trunk. The origin of the anterior spinal artery is 

 normal. The posterior inferior cerebellar arteries are small and 

 arise from the basilar. A similar anomaly has been reported by 



