MUSCLES OF THE TONGUE. 



149 



Fig. 37. 



glossus, c, p. 99) enter the under surface of the tongue, between the 

 stylo-glossus and the lingualis. After entering that surface by separate 

 bundles, they are bent round the margin, and 

 form, with the two preceding muscles, a 

 stratum on the dorsum of the tongue. 



The third part of the muscle, or the chondro- 

 glossns, F, is distinct from the rest. About 

 two or three lines wide at its origin from the 

 root of the small cornu, and from part of the 

 body of the os hyoides, the muscle entering 

 beneath the upper lingualis, passes obliquely 

 inwards over the posterior third of the dorsum, 

 to blend with the hyo glossus. 



Cortex of the tongue. The muscles above 

 described, together with the superficial lingua- 

 lis, constitute a cortical layer of oblique and 

 longitudinal fibres, which covers the tongue, 

 except below where some muscles are placed, 

 and resembles "a slipper turned upside 

 down." This stratum is pierced by deeper 

 fibres. 



The genio-hyo-glossus (fig. 38, A ) enters the 

 tongue vertically on the side of the septum, 

 and perforates the cortical covering to end in 

 the submucous tissue. In the tongue the 

 fibres spread like the rays of a fan from apex 

 to base, and are collected into bundles as they 

 pass through the transversalis. The most pos- 

 terior fibres end on the hyo-glossal membrane 

 and the hyoid bone ; and a slip is prolonged 

 from them, beneath the hyo-glossus, to the up- 

 per constrictor of the pharynx. A vertical section at a future stage will 

 show the radiation of its fibres. 



The pharynyeo-glossus (glosso-pharyngeus), or the part of the upper 

 constrictor attached to the side of the 

 tongue, passes amongst fibres of the hyo- 

 glossus, and is continued with the trans- 

 verse muscle to the septum. 



The intrinsic muscles (fig. 38) are three 

 in number in each half of the tongue, viz., 

 transversalis, with a superior and an infe- 

 rior lingualis. 



Dissection. To complete the prepara- 

 tion of the inferior lingualis on the right 

 side, the fibres of the stylo-glossus covering 

 it in front, and those of the genio-hyo- 

 glossus over it behind, are to be cut 

 through. 



The superior lingualis (fig. 37, A ) may 

 be shown, on the left side, by taking the 

 thin mucous membrane from the upper surface from tip to base. 



The transversalis (fig. 38, c ) may be laid bare on the right side, by 

 cutting away on the upper surface the stratum of the extrinsic muscles 



MUSCLES ON THE SURFACE OF 

 THE TONOUE. 



A. Superficial lingualis. 



B. Stylo-glossus. 

 c Hyo-glo->sus. 

 D. Palato-glossus. 

 F. Chondro-glossus. 



<>. Phaiytigeo-glossus. 



H. Septum litiguie (Zaglas). 



INTRINSIC MUSCLES OF THE TONGUE. 



A, Genio-hyo-glossus. 



B. Septum linguffl. 

 c. Trausversalis. 



D. Inferior lingualis (Zaglas). 



