OF THE MUSCLES. 107 



surface of the wing of the atlas ; and to the capsular liga- 

 ment of the odontoid process. Action. To rotate the head ; 

 and to guard the capsular ligament. 



Sterno maxillaris (Plate III. 5). Origin. From the 

 cariniform process of the sternum. Insertion. Into the 

 angle of the lower jaw. Action. To bend down the head ; 

 and to curve the neck ; it also may aid in opening the 

 mouth, though, from its position, it cannot do so with 

 much activity. 



Sterno-thyro-hyoideus (Plate III. 6. Fig 5.5). 

 Origin. From the cariniform process of the sternum ; about 

 the middle of the trachea the muscle becomes tendinous ; 

 from this tendon it divides into two heads. Insertion. Into 

 the spur process of the os hyoides by one head ; and by the 

 other head, into the thyroid cartilage of the larynx. Ac- 

 tion. To regulate the downward motions of the larynx ; and 

 to pull downward the os hyoides. 



Scalenus (Plate III. 10. Fig ^^ . 4). Origin. From the 

 middle of the first rib. Insertion. Into the transverse pro- 

 cesses of the fourtli, fifth, sixth, and seventh cervical ver- 

 tebrae. Action. To depress the neck ; or to draw the first 

 rib forward. 



LoNGUs COLLI. Origin. From the transverse processes, 

 bodies, and inferior spines of the first six dorsal, and last six 

 cervical vertebrae. Insertion. Into the inferior spines of all 

 the cei'vical vertebrtie, by tendinous cords. Action. To bend 

 downward the neck. 



Depressor capitis major (Fig 5.9). Origin. From the 

 transverse processes of the second, third, fourth, fifth, and 

 sixth cervical vertebras. Insertion. Into the base of the 

 cranium, by tendon. Action. To depress the head, both 

 powerfully and rapidly. 



Depressor capitis minor. Origin. From the inferior of 

 the atlas. Insertion. Behind the former muscle, into the 

 base of the cranium. Action. To aid the major. 



Rotator capitis internus. Origin. From the inferior 

 surface of the wing of the atlas. Insertion. Into the styloid 

 process of the occiput, upon the inner side. Action. To 

 rotate the head upon the atlas ; and to antagonize the rotator 

 capitis anterior. 



There are also several minute muscles around the cervical 

 vertebrae, which serve to move one bone upon another ; and 



