226 



TSE MUSOLES. 



of the tead, thinner and narrower below than above, and formed entirely of 

 fleshy fibres which extend transversely from its anterior to its posterior 

 border. Inferiorly, it is composed of a small fasciculus, which is 

 distinguished from the principal portion by the slightly different direction 

 of its fibres, and which covers in part the external surface of the muscle. 



Fig. 11] 



HYOIDEAL AND PIIAEVNGEAL EEGIONS. 



1, Neck of inferior maxilla ; 2, Hard palate ; 3, Molar teeth ; 4, Buccal membrane ; 5, 

 Submaxillary glands; 6, Soft palate; 7, Tendon of hj-oideus magnus through 

 which the tendon, 8, of she digastricus passes; 9, Lower portion of digastncus; 

 10, Stylo-hyoideus ; 11, Buccal nerve; 12, Zygomatic arch ; 13, Orbital branch 

 of fifth pair of nerves ; 14, Articular process of temporal bone ; 15, Right cornu of 

 hyoidbone; 16, Hyo-glossus longus, or Kerato-glossus ; 17, Lingual nerve ; 18,18, 

 Tongue; 19, Angle of left branch of inferior maxilla; 20, Submaxillary gland, 

 left side ; 21, Subscapulo-hyoideus ; 22, Great hypoglossal nerve ; 23, Hyo- 

 thyroideus ; 24, Sterno-hyoideus ; 25, Sterno-thyroideus ; 26, Subscapulo hyoi- 

 deus ; 27, Thyroid gland ; 28, External carotid artery ; 29, Pneumogastric nerve ; 

 30, Stylo-hyoideus ; 31, Genio-hyoideus. 



Attachments. — It originates from the mylo-hyoid line by the anterior 

 extremities of its fibres. Its movable insertion takes place on the inferior 

 faceof thehyoid body, on its anterior appendix, and on a fibrous raphe which 

 extends from the free extremity of this appendix to near the genial surface, 

 and which unites, on the median line, the two mylo-hyoidean muscles. 



Belations. — By its external face, with the inferior maxilla, the digastric 

 muscle, and the submaxillary lymphatic glands. By its internal face, with 

 the sublingual gland, the Whartonian duct, the hypoglossal and lingual 

 nerves, the genio-glossus, hyo-^lossus longus and brevis, and genio-hyoideus. 

 Its superior border responds to the internal pterygoid. 



_ Action. — In uniting on the median line with that of the opposite side, 

 this muscle forms a kind of wide band or brace on which the tongue rests. 

 When it contracts, it elevates this organ, or rather applies it against the 

 palate. 



2. Genio-hyoideus. 



Form — Structure — Situation. — A fleshy, elongated, and fusiform | 

 tendinous at its extremities, but especially at the inferior one, and ap 

 with its fellow of the opposite side, to the mylo-hyoidean brace. 





