186 THE HEAD AND NECK 



the profunda veins (ranine) can be seen shining through it. 

 Near the tip of the tongue, and embedded in the muscles on its 

 under surface, there is a collection of mucous and serous glands, 

 which occasionally give rise to small cysts. The under surface 

 of the tongue is attached to the floor of the mouth by a fold of 

 mucous membrane, termed thefrenulum, which may sometimes 

 be so short as to interfere with the free movement of the organ 

 (" tongue tie "). 



The submaxillary (Wharton's) duct opens on a small papilla, 

 which is placed lateral to the point where the frenulum of the 

 tongue joins the mucous membrane of the floor of the mouth. 

 The plica sublingualis, which overlies the sublingual gland and 

 is pierced by its ducts, runs backwards and laterally from the 

 papilla. 



The tongue is plentifully supplied with lymph vessels, from 

 which arise the large collecting trunks, viz. (i) apical, (2) mar- 

 ginal, (3) basal, (4) central. 



(i) The Apical Lymph Vessels drain the tip of the tongue 

 and open into the submental lymph glands. Some, however, 

 pass directly to join the lower anterior group of the deep cervical 

 lymph glands at the level of the sixth cervical vertebra, and in 

 consequence these glands may be involved at a very early stage 

 in malignant disease of the tongue. (2) The Marginal Lymph 

 Vessels drain the lateral borders of the tongue. Some of them 

 join the submaxillary lymph glands, but the remainder run 

 backwards and downwards to open into the deep cervical lymph 

 glands, which lie on the carotid sheath opposite the third, fourth, 

 and fifth cervical vertebrae. (3) The Basal Lymph Vessels 

 drain the dorsum of the tongue. After running backwards 

 towards the lower pole of the palatine tonsil, they pierce the 

 superior constrictor, and open into the upper anterior group of 

 the deep cervical lymph glands under cover of the posterior 

 belly of the digastric. They communicate very freely with the 

 corresponding vessels of the opposite side, a point of great 

 importance clinically. (4) The Central Lymph Vessels drain 

 the substance of the tongue and descend between the genio- 

 glossi, to terminate in the lower anterior group of the deep 

 cervical lymph glands. 



Recurrence of malignant disease of the tongue usually mani- 

 fests itself in the lymph glands and not in the mouth. In 

 excision of the tongue for malignant disease it is of the greatest 

 importance to remove all the lymph glands which drain the area 



