OPERATION ON SUBMAXILLARY GLAND 211 



its base, giving off first the lingual artery, secondly the facial. Just 

 as the carotid begins to pass in front of the digastric, it is crossed by 

 the hypoglossal nerve, h, and is accompanied by filaments of the 

 sympathetic. At the upper angle of the triangle several structures pass 

 from it to the hilum of the gland, close to the margin of the digastric. 

 These are : 1, the duct ; 2, the nerves ; 3, the principal artery of the 

 gland. The artery is given off by the facial. It lies beneath the 

 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, m, cutting its fibres 

 across about their middle, and reflect the upper half, taking care not 

 to injure the mylo-hyoid nerve 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 digastric 

 and masseter 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 a little towards the middle line with the fingers, 

 and follow the lingual nerve to the ramus of the jaw. A small twig, c, 

 will then be seen, which passes off 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 chorda tympani. In the 

 angle between the chorda and the lingual lies the submaxillary gan- 

 glion. 11. Isolate the chorda and pass a thread under it, so that 

 the nerve may be raised from its place at will. 12. To reach the 

 sympathetic divide the hypoglossal nerve, h, just where it crosses the 

 carotid, and lift up its central end. Close to the inside of the carotid 

 lies the vagus, and when this is raised the sympathetic is seen lying 

 underneath and to the inner side of it. The sympathetic separates 

 from the vagus at this point, and passes to the superior cervical gan- 

 glion. From the ganglion, fibres accompany the carotid and enter 

 the gland along with its arteries. The ganglion can easily be found 

 by following the carotid filaments backwards. 13. Place a cannula 

 in the submaxillary duct. The ducts of the submaxillary and sub- 

 lingual pass along the middle of the triangle close to one another. 

 The submaxillary duct lies closer to the ramus of the jaw, and is 

 larger than the sublingual duct. Isolate it slightly with an aneurism 

 needle. Pass under it a thread for the purpose of tying in the 

 cannula. Pass 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 1>\ the thread 



