iz6 SURGICAL APPLIED ANATOMY. [Chap. vin. 



lined with ciliated epithelium may sometimes be found 

 in the same situations. All these structures are the 

 remains of the neck of the central diverticulum which 

 is protruded from the ventral wall of the pharynx in 

 the embryo, and from which the chief part of the 

 thyroid gland is formed. The foramen caicum on the 

 tongue indicates the spot where this diverticulum 

 leaves the pharynx. Ducts lined with epithelium 

 have been found leading from the foramen caecum to 

 accessory glands about the hyoid bone. It is prob- 

 ably from these glandular and epithelial collections 

 about the hyoid bone that certain deep-seated forms 

 of cancer of the neck are developed. Some of these 

 take the form of malignant cysts described by the 

 author (Path. Soc. Trans., 1886). 



Much adenoid tissue lies at the back of the 

 tongue about the base of the epiglottis. The hyper- 

 trophy of this tonsil-like tissue (the lingual tonsil) 

 may lead to troublesome symptoms by impairing the 

 movements of the epiglottis. 



Excision. Many different methods have been 

 adopted for the removal of the entire tongue. It has 

 been removed through the mouth by the ecraseur or 

 the scissors, the latter operation being performed with 

 or without previous ligature of the lingual arteries in 

 the neck. It is difficult, however, to fully expose the 

 deeper attachments of the organ through the compara- 

 tively small orifice of the mouth. To obtain more 

 room the cheek has been slit up in one procedure, 

 while the lower lip and symphysis of the lower jaw 

 have been divided in another. 



In another series of operations the tongue has 

 been reached, or the organ has been fully exposed, by 

 an incision made between the hyoid bone and the 

 inferior maxilla. More recently Kocher has exposed 

 the tongue from the neck, and has reached it by an 

 incision commencing near the ear and following the 



