98 MUSCULAR SYSTEM. 



arising from the middle and inferior part of the semicircular por- 

 tion of the same bone. 



Direction. — Oblique : from behind, ft)rwards ; and from above, 

 downwards. 



Relation. — Below, with the stylo-maxillaris, di^astricus, and 

 parotid gland; above, with the corner of the os hyoides, ninth 

 pair of nerves, and lingual vessels: externally, with the pterygoi- 

 deus internus ; internally, with the larynx and recurrent nerve. 



Structure. — Tendinous and fleshy at its posterior attachment; 

 ending in a slender tendon, anteriorly. 



Action. — To draw the body of the os hyoides still nearer to the 

 sideof the jaw, and thereby assist in the dilatation of the glottis. 



HYoiDEUS PARVUS. — Kercito-hijoideus Parvus. 

 Situation. — Above and rather before the preceding muscle. 

 Form. — Small, flat, triangular. 



Attachment. — To the body and appendix of the os hyoides, 

 filling up the triangular space between them. 

 Action. — To approximate these parts. 



STYLO-HYOIDEUS. 



Situation. — I nfero -anterior part of the neck. 



Figure. — Quadrilateral. 



Attachment. — Posteriorly, to the front of the styloid process of 

 the occipital bone; anteriorly, to the angle of the hyoideal cornu. 



Relation. — Externally, with the parotid gland ; internally, with 

 the guttural membrane: inferiorly, with the stylo-maxillaris; pos- 

 teriorly, with the obliquus capitis superior. 



Structure. — Fleshy, with tendinous intersections. 



Action. — To retract, and at the same time elevate, the cornu 

 of the OS hyoides, 



7.— GLOSSAL REGION. 

 The muscles of this region form, collectively, the substance 

 of the tongue : their number ^nd variety account for the well- 

 known mobility of that organ. 



H Y o-G LO .s^ u s LONG US. — Kerato-'glossus. 



Situation. — Along the base and side of the tongue. 



Form. — Long, narrow : flattened upon its sides. 



Attachment. — Posteriorly, to the cornu of the os hyoides, a 

 short distance from its junction with the appendix; anteriorly, 

 infero-lateral parts of the tongue. 



Relations. — Externally, with the mylo-hyoideus ; internally, 

 with the hyo-glossus brevis; inferiorly, with the gustatory nerves. 



