MUSCLES OF THE NECK 319 



Action. — Contracting alone, it would Ijciid tlie neck to one .side. 

 Acting together witli its fellow on the opposite side, it elevates and 

 extends the head. 



Trachelo-Mastoideus. — Situated on the side of the neck lieneath the 

 splenius. It is a long muscle, composed of two fleshy divisions whicli pass 

 from the head downwards to the anterior extremity of the back. 



Oi'igin. — It takes its origin from the transverse processes of the first 

 two dorsal vertebrfe, ami from the articular tubercles of the last six ceivical 

 vertebrse. 



Insertion. — Into the mastoid process of the temporal bone, and to the 

 wing of the atlas l)y a flat tendon common to the splenius and mastoido- 

 humeralis. 



Action. — When acting alone, the trachelo-mastoideus draws the head 

 and neck to one side. When acting with the corresponding muscle of the 

 other side, it raises tlie head. 



Spinalis Colli. — Five thick, short strands of muscle deeply seated on 

 the side of the neck in proximity with the bones. They are in continuation 

 of similar short muscular fasciculi, presently to be noticed, in the regions of 

 the back and loins. 



Origin. — From the oblique processes of the five posterior cervical 

 vertebrae or neck bones. 



Insertion. — Into the spinous processes of the 2nd, 3rd, 4th, 5th, and 

 6th of the same. 



Action. — To extend the neck, and to fix the Ijunes in accordance with 

 the action of other of the cervical muscles. 



Intertransversales Colli. — These are six short muscles placed on the 

 side of the neck iu appusititjn with the vertebrce. Each extends from the 

 ol)lic|ue process of one vertebra to the transverse process of the one preced- 

 ing it, except in the case of the two first. 



Action. — To draw the neck to one side. 



Obliquus Capitis Superior. — A short, thick, scjuare muscle situated 

 on tlie side of tlie poll. It is largeK' intersected by strands of tendinous 

 tissue, and covers over the articulation between the occi^jut and the first 

 cervical vertebra. 



Origin. — From the anterior border and under surface of the wing of the 

 atlas. 



Insertion. — Into the mastoid crest and tlie styloid process of the 

 occiput. 



Actio7i. — To incline the head to one side and to assist in extending it. 



Obliquus Capitis Inferior is a thick, fleshy muscle, somewhat longer 

 than the last described, and situated immediately below it. 



