MUSCLES OF THE BODY. 115 



bone through their insertion into the tendon of the stylo- 

 hyoid (d). 



Relations. Outer surface with the submentalis (Fig. 64, c) 

 and the digastric (Fig. 65, b}. Lateral edge with the masseter 

 (a), the digastric (), and the mandibula. Caudal border with 

 the stylohyoid (d}. Inner (dorsal) surface with the geniohyoid 

 (Fig. 67, g), the hyoglossus (Fig. 67, //), and the genioglossus 

 (Fig- 67,7). 



Action. Raises the floor of the mouth and thus brings the 

 hyoid forward. 



M. ceratohyoideus. 



Origin, the two proximal pieces of the cranial horn of the 

 hyoid. The fibres pass caudad parallel to one another and 

 within the middle constrictor of the pharynx. 



Insertion into the whole length of the caudal cornu of the 

 hyoid bone. 



Relations.- Outer surface with the middle constrictor of the 

 pharynx. Inner surface with the pharynx. 



Action.- Draws craniad the body of the hyoid by bringing 

 its cornua together and bending the joint between the t\vo 

 pieces of the cranial cornua. 



The muscles connecting the hyoid and the tongue are 

 described in connection with the description of the tongue. 



III. MUSCLES OF THE BODY. 

 . i . Muscles of the Back. 



A. MUSCLES OF THE SHOULDER (connecting the forelimb 

 with the back) (Fig. 68). 



M. trapezius. The trapezius muscle is divided in the cat 

 into three portions, the spinotrapezius, the acromiotrapezius, 

 and the clavotrapezius. 



M. spinotrapezius, or trapezius inferior (Fig. 68,7'). The 

 spinotrapezius (caudal part of the human trapezius) is a flat 

 triangular muscle. 



Origin from the tips of the spinous processes of all or 

 nearly all the thoracic vertebrae and from the intervening 

 supraspinous ligament. The origin may extend from a point 

 anywhere between the first and fourth spines to any point 

 between the eleventh and thirteenth. 



