II32 



A MANUAL OF ANATOMY 



Insertion. — (i) The under surface of the tongue close to the median 

 line, and extending from near the tip to the root ; (2) the inner part 

 of the anterior surface of the body of the hyoid bone close to its 

 upper margin ; and (3) slightly into the side of the pharynx, where 

 the fibres blend with those of the middle constrictor muscle. 



Nerve- supply. —The hypoglossal nerve, the branches of which 

 enter the outer surface of the muscle. 



The upper or anterior fibres arch upwards and forwards, and the 

 lower downwards and backwards, whilst the intervening fibres 

 spread out in a diverging manner. 



Action. — (i) The entire glossal fibres depress the tongue at the 



Tip of Styloid Process of 

 Temporal Bone 



Stylo-hyoid Ligament ,, 

 (upper part) 



Stylo-glossus 



Palato-glossus 



Great Cornu of Hyoid 

 Bone 



Dorsum of Tongue 



Hyo-glossus / 



/ 

 / 



Lingualis Inferior 



Mandible (in section) 

 / Genio-hyo-glossus 



Genio-hyoid 



Fig. 463. — The Extrinsic Muscles of the Tongue. (The Lingualis 

 Inferior is an Intrinsic Muscle). 



median line, and, along with those of the opposite side, they give 

 rise to an antero -posterior groove, or gutter, on the dorsum of the 

 organ ; (2) the posterior glossal fibres draw forwards the tongue, 

 so as to cause its tip to be protruded from the mouth ; (3) the 

 anterior glossal fibres retract the tip of the tongue when it has been 

 protruded from the mouth ; and (4) the lower or posterior (hyal) 

 fibres elevate the hyoid bone, and draw it forwards. 



The muscle is fan-shaped. The internal surface is closely applied 

 to that of its fellow of the opposite side. The external surface is 



