112 FISTULA AND POLL-EVIL 



brae. It inserts to tubercles which occur at 

 the junction of the basilar part of the occipital 

 bone with the body of the sphenoid. These 

 muscles (the pair) may be said to form a roof 

 for a part of the pharynx. 



The blood supply of the poll is from three 

 sources: The occipital, the superior cervical 

 and the vertebral arteries. The first named 

 is, however, the chief one. It is a radical of 

 the carotid and passes to the region of the poll 

 through the large foramen in the wing of the 

 atlas. Its branches anastomose with the other 

 two. The branches are numerous and often 

 through the influence of the disease become 

 greatly enlarged. In the operation for poll- 

 evil the incision being a standard one, made 

 irrespective of blood vessels, there is nothing of 

 importance to say about avoiding them, ex- 

 cept that lateral invasion into the region of the 

 alar foramen through which the occipital passes 

 must be made cautiously. In short, no especial 

 effort except this one, is ever made to avoid 

 arteries. 



The 7ierve supply is of no especial impor- 

 tance. It is derived from the spinal accessory 

 and the first two spinal nerves, none of which 

 is ever seen in the operation, nor is a solution 

 on the continuity of their branches attended 

 with anv observable harm. 



