MUSCLES OF THE NECK 319 



Action. Contracting alone, it would bend the neck to one side. 

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

 extends the head. 



Traehelo-MastoidetlS. Situated on the side of the neck beneath the 

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

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



Origin. -It takes its origin from the transverse processes of the first 

 two dorsal vertebrse, and from the articular tubercles of the last six cervical 

 vertebree. 



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

 wing of the atlas by 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 the 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 

 vertebrte 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 bones 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 in apposition with the vertebrae. Each extends from the 

 oblique 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, square muscle situated 

 on the side of the poll. It is largely intersected by strands of tendinous 

 tissue, and covers over the articulation between the occiput 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 the styloid process of the 

 occiput. 



Action. 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. 



