470 DIGESTION. 



by the facial at the upper angle of the triangle. It lies beneath 

 tin- nerves, but is easily reached by drawing them aside. 8. 

 Carefully isolate the digastric by a director or aneurism needle 

 from all the structures just mentioned. Divide it close to its 

 insertion into the temporal bone. 9. Divide the mylo-hyoid 

 muscle, cutting its fibres across about their middle, and reflect 

 the upper half, taking care not to injure the mylo-hyoid never 

 which lies upon it, and tying all the veins which come into 

 view on its surface with a double ligature. This brings into 

 view the lingual nerve L, which issues from under the ramus 

 of the jaw just opposite the groove between the masseter and 

 digastric muscles, and after passing across the floor of the 

 triangle towards the middle line, enters the mucous membrane 



of the mouth 10. Draw the parts alittle towards the middle 



line with the fingers, and follow the lingual nerve to the 

 ramus of the jaw'. A small twig T will then be seen, which 



a oil' from its posterior aspect, bends down, making a sort 

 of loop, and then runs backwards to the gland in close relation 

 to the duct. This nerve is the cJmrda tijuipani. In the angle 

 between the eorda and the lingual lies the submaxillary gan- 

 glion. 11. Isolate the chorda tym/tani, pass a thread under 

 it. and tie the two ends together, so that the nerve maybe 



1 from its place at will. 12. Isolate the lingual nerve 

 clost- to its entrance into the month, and pass a thread under 

 it. 1,'{. To reaeh tin- sympathetic, divide the hypoglossal nerve 

 P just where it crosses the carotid, and raise up its central 

 end. Close to the inside of the carotid lies the vagus, and 

 when this is raised the sympathetic is seen underneath and 

 inside of it. The sympathetic separates from the vagus at 

 this point and goes to the superior cervical ganglion (see fig. 

 :;u!>). From the ganglion, fibres accompany the carotid and 

 enter the gland, some along with the chief artery (0), and 

 others with the other artery 1". The ganglion can easily be 

 found by following the carotid filaments backwards. 14. Place 

 a e:mula in the submaxillary duct. The ducts of the sub- 

 maxillary and sublingual glands pass along the middle of the 

 triangle close to each other. The submaxillary duct lies nearer 

 the ramus of the jaw, and is larger than the sublingnal duct. 

 Isolate it slightly with an aneurism needle. Pass undev it a 

 thread for the purpose of tying in the eanula. Place under 

 the duct a smooth splinter of wood or a piece of card half an 

 inch long by one-eighth of an inch wide, on which it may rest. 

 Close the duct as near the mouth as possible with a clip, or 

 tie a thread round it so as to obstruct it. Raise the chorda 

 by the thread which has been passed round it, irritate it by a 

 weak interrupted current; the purpose of this is to distend 

 the duct with secretion, and thus render the introduction of a 

 eanula much easier. Let an assistant lay hold of one edge of 



