DISSECTION OP THE HEAD AND NECK. 197 



The Lingual Fibrous Cord— This is a fibrous cord extending along 

 the middle line of the dorsum of the tongue, immediately beneath the 

 mucous membrane. With a sharp scalpel incise the tongue along this 

 line to the depth of half an inch or more, beginning the incision be- 

 hind the circumvallate papillae, and terminating it in the free portion of 

 the tongue. This will expose the cord in its entire length. It is a little 

 less in thickness than a goose quill. It begins between the two large 

 circumvallate papillaj, and it terminates towards the junction of the free 

 and the fixed portion of the tongue, being about seven inches in length. 



Lingual Glands. — These are aggregated as a thick layer under the 

 mucous membrane at the upper part of the dorsum. The mucus Avhich 

 they secrete coats the bolus of food as it passes through the fauces. They 

 are of the racemose type, and their ducts open on little tubercles of the 

 mucous membrane. 



Directions. — The mucous membrane is to be raised from the sublingual 

 gland and the sides of the tongue. It is convenient to describe the 

 gland here, although it is not a part of the tongue. 



The Sublingual Gland (Plate 30). This, the smallest of the 

 salivary glands, is placed at the floor of the mouth, and at the side of, 

 rather than under, the tongue. It extends from the level of the 5th 

 molar tooth to the symphysis. It is in contact outwardly with the 

 mylo-hyoid muscle. Inwardly it is related to the stylo-glossus, genio- 

 glossus, and genio-hyoideus muscles, to Wharton's duct, and to the lingual 

 nerves. Its posterior border is included between the mylo-hyoid and the 

 genio-hyoid muscles, and is related inferiorly to the submental artery. 

 Its anterior border projects the mucous membrane at the side of the 

 tongue, so as to form the sublingual ridge. The upper extremity is 

 related to the lingual nerve and vein. It is a compound racemose gland, 

 and it discharges its secretion by from fifteen to twenty ducts — the dticts 

 of Riviniu^ — which perforate the little tubercles on the sublingual ridge. 



Directions. — The gland is to be carefully excised without injury to 

 Wharton's duct or the adjacent vessels and nerves. It will be observed 

 to receive a nerve from the lingual branch of the 5th, while its vessels 

 are branches of the submental artery and vein. 



Wharton's Duct (Plates 30 and 31) is the excretory canal of the sub- 

 maxillary gland. Leaving the lower extremity of the gland, where it is 

 crossed outwardly by the submaxillary artery, it passes between the 

 mylo-hyoideus outwardly, and the great hyo-glossus and the stylo-glossus 

 muscles inwardly, its position here being immediately behind the body 

 of the hyoid. A little in advance of the superior extremity of the 

 subungual gland, it passes to its inner side, and is continued downwards 

 between the gland and the genio-glossus muscle. Finally, it opens on 

 the summit of the flattened papilla, or harh, at the side of the frsenum 

 lingure. As the duct passes to the inner side of the sublingual gland, 



