THE TONGUE 415 



the chondroglossus, the transverse lingualis, the vertical 

 lingualis, and the inferior lingualis. These muscles are invested 

 by a submucous fibrous layer, covered by a mucous membrane. 

 It consists of symmetrical halves, separated from each other 

 by a fibrous septum. Each half of muscular fibers is arranged 

 in various directions, containing many glands, arid fat, and 

 supplied by vessels and nerves. For purposes of description 

 the tongue is divided into, a body, base, apex, dorsum, margins, 

 and inferior surface. 



The body (corpus linguae) is composed of striated muscle 

 and forms the greatest bulk of the organ. 



The base, or root (radix linguae), is directed backward, is 

 convex and held to the hyoid bone by the hyoglossus and 

 geniohyoglossi muscles and membrane; with the epiglottis 

 by the glossoepiglottic folds, also attached to the soft palate 

 by the anterior pillars of the fauces, and to the pharynx by 

 the palatopharyngei muscles, and the mucous membrane. 



The apex (apex linguae) is thin and narrow, resting against 

 the inner surface of the lower incisor tdfeth. 



The dorsum (dorsum linguae) is convex from before back- 

 ward, when at rest. It presents for examination a median 

 longitudinal raphe (sulcus medianus linguae), which ends in 

 a depression at the posterior part; the foramen cecum (foramen 

 cecum linguae Morgagni), from which a shallow groove 

 passes outward and forward on each side to the lateral margins ; 

 this is called the sulcus terminalis of His. The projections 

 of papillae are seen through the stratified squamous epithelial 

 cells. They are: (1) The filiform (papillae filiformes), small 

 and scattered over the apical two-thirds (dorsum and margins) 

 of the tongue; (2) the fungiform papillae (papillae fungiformis), 

 scattered (but less numerous than the filiform) over the 

 dorsum, and are more numerous at the sides and apex (they 

 are readily recognized by their large size and deep red color); 

 (3) the circumvallate papillae (papillae vallatae) are large, 

 but only eight to twelve in number. They are arranged in 

 a V-shaped manner just in front of the foramen cecum, and 

 the sulcus terminalis. 



The arteries of the tongue are derived from the lingual, 

 the facial, ascending pharyngeal (all branches of the external 

 carotid artery). The veins open into the internal jugular. 

 The lymphatic vessels from the anterior half of the tongue, 



