1580 



HUMAN ANATOMY. 



longitudinal system, the various parts of which can act separately, turns the tip in 

 any direction. The stylo-glossus and palato-glossus raise the posterior portion, 

 particularly at the edges, but the latter probably acts more on the palate than on the 

 tongue. 



Vessels. — The principal arteries supplying the tongue are branches of the 

 lingual, elsewhere described (page 735). Although there may be a trifling anasto- 

 mosis at the tip between the vessels of the opposite sides, there is no communication 

 sufficient to re-establish the circulation at once, so that ligation of either artery 

 will render that half of the tongue bloodless for an operation. The veins consist of 

 four sets on each side, communicating freely with one another. They are ( i ) the 

 dorsal veins forming a submucous plexus on the back of the tongue above the larynx 

 and joining those of the tonsil and pharynx, (2) two veins accompanying the artery 

 and sometimes forming a plexus about it, (3) two with the lingual nerve, (4) two 

 with the hypoglossal nerve. Of these latter, the one below the nerve is the larger 

 and is the ranine vein, running on the under surface of the tongue on either side of 

 the frenum. The lymphatics present a rich net-work on the anterior two-thirds of 

 the dorsum. The multitude of spaces throughout the organ communicate with lym- 



FiG. 1341. 



Longitudinal fibres 



Glands 



Portion of sublingual gland 



Vertical fibres 



nsverse fibres 



Septum Genio-glossus Hyo-glossus 



Transverse section of tongue of child, through middle third. X 3. 



phatics. Some from the median part empty into the suprahyoid glands, but most 

 go to the submaxillary and to the deep cervical glands. 



Nerves. — The motor fibres are supplied by the hypoglossal, aided probably by 

 the facial through the chorda tympani. Those of common sensation are from the 

 lingual branch of the fifth for the anterior two-thirds and from the glosso-pharyngeal 

 for the remainder, excepting the region just in front of the epiglottis, which is 

 supplied by the superior laryngeal from the \'agus. The glosso-pharyngeal area 

 somewhat overlaps the posterior third, as it supplies the circumvallate and foliate 

 papilke. The chief fibres of special sense are derived from the glosso-pharyngeal, 

 their principal distribution being to the taste-buds on the circumvallate papilke. Re- 

 garding the source of the taste-fibres to the anterior parts of the tongue opinions 

 still differ. According to many anatomists, these fibres reach their destination 

 through the chorda tympani, since the latter nerve is supposed to receive taste- 

 fibres from the ninth by way of the pars intermedia of Wrisberg, which accompanies 

 the facial. According to Zander,' Dixon, ^ Spiller,^ and others, however, the view 

 attributing fibres of special sense for the anterior part of the tongue partly to the 

 fifth nerve is correct. 



Growth and Changes. — At birth the tongue is remarkable chiefly for its want 

 of depth, as shown in a median section, which depends on the undeveloped condition 

 of the jaws. This is gradually corrected coincidently with the growth of the face. 



' Anatomischer Anzeiger, Bd. xiv., 1897. 



^ Edinburgh Medical Journal, 1897. 



^ University of Pennsylvania Medical Bulletin, March, 1903. 



