DISSECTION OF THE TONGUE. 



Muscular 

 cortex of 

 tongue. 



Geuio- 

 glossus in 

 the tongue ; 



its posterior 

 libres. 



Constrictor 

 in the 

 tongue. 



Intrinsic 

 muscles. 



First show 

 inferior, 



then supe- 

 rior lin- 

 gualis, 



then trans- 

 versalis. 



Trace the 

 nerves. 



Transver- 

 salis is hori- 

 zontal : 



attach- 

 ments ; 



Cortex of the tongue. The muscles above described, together with 

 the superficial lingualis, constitute a cortical layer of oblique and 

 longitudinal fibres, which covers the tongue, except below where 

 the genio-glossus and inferior lingualis muscles are placed, and 

 resembles " a slipper turned upside down" (Zaglas). This stratum 

 is pierced by the deeper fibres. 



The GENIO-GLOSSUS (fig. 243, A) enters the tongue vertically by 

 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 transverse laminae 

 as they pass through the trans versalis. The hindmost fibres end on 

 the hyo-glossal membrane and the hyoid bone ; and a slip is pro- 

 longed from them, beneath the hyo-glossus, to the upper constrictor 

 of the pharynx. A vertical section at a future stage will show th< 

 radiation of its fibres. 



The PHARYNGEO-GLOSSUS (fig. 242, G), or the fibres of the upper 



constrictor attached to the side oi 

 B the tongue, passes beneath th< 



fibres of the hyo-glossus, and is 

 continued with the transverse 

 muscle to the septum. 



The intrinsic muscles are four 

 in number in each half of the 

 tongue, viz., transversalis, a supe- 

 rior and an inferior lingualis, and 

 a set of perpendicular fibres. 



Dissection. To complete the 

 preparation of the inferior lin- 

 gualis on the right side, the fibres 

 of the stylo-glossus covering it in 

 front, and those of the hyo-glossus 

 over it behind are to be cut 

 through. 



The superior lingualis (fig. 242, A) may be shown on the left side, 

 by taking the thin mucous membrane from the upper surface from 

 tip to base. 



The transversalis ma} be laid bare on the right side, by cutting 

 away on the upper surface the stratum of the extrinsic muscles 

 already seen ; and by removing on the lower surface the inferior 

 lingualis and the genio-glossus, after the former muscle has been 

 examined. 



The nerves of the tongue are to be dissected on the left half as 

 well as the part will admit ; but a fresh specimen will be required 

 to follow them satisfactorily. 



The TRANSVERSE LINGUALIS MUSCLE (fig. 243, c) forms a hori- 

 zontal layer in the substance of the tongue from base to apex. The 

 fibres are attached internally to the side of the septum, and are 

 directed thence outwards, the posterior being somewhat curved, to 

 their insertion into the submucous tissue at the side of the tongue. 



FIG. 243. TRANSVERSE SECTION OF 

 THE TONGUE. 



A. Geuio-glossus. 



B. Septum linguae, 

 c. Transversalis. 



D. Inferior lingualis 

 las.) 



(After Zag- 



