HEALTH AND DISEASE 



Origin. From the outer surface of the superior spinous process of the 

 second cervical vertebra (axis or dentata). 



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



Action. To rotate the atlas on the dentata. Its action is shown in a 

 striking manner when the horse shakes his head. 



RectUS Capitis Posticus Major. A short, fleshy muscle placed 

 beneath that last described, and partly divisible into two portions. 



Origin. From the superior spinous process of the dentata or second 

 cervical vertebra. 



Insertion. Into the posterior part of the occipital bone. 



Action. Assists the complexus major in extending the head on the 

 neck. 



RectUS Capitis PosticUS Minor. A small, wide, flat muscle placed 

 beneath that last described, and extending over the articular capsule of the 

 joint formed by the occiput and the first cervical vertebra. 



Origin. From the superior surface of the atlas. 



Insertion. Into the posterior surface of the occiput, 



Action. It assists in extending the head on the neck. 



Cervical Panniculus. This is a thin layer of muscular tissue spread 

 over the front of the neck, extending from the breast below, upward, to 

 behind the jaws, and on to the sides of the face. 



Below, it is attached to the cariniform cartilage of the sternum, to which 

 it converges from either side. Above, it becomes closely adherent to the 

 muscles in front of the neck, which it braces and supports. 



Cervical Trapezius. See muscles of the back. 



Mastoido-Humeralis. This is a long, broad, fleshy muscle, extending 

 from the top of the head downward along the side of the neck over the 

 point of the shoulder to the humerus or upper arm bone. 



Origin. Above from the mastoid process and crest of the occipital 

 bone, and from the transverse processes of the first four cervical ver- 

 tebrae. 



Insertion. Into the upper third of the ridge on the outer part of the 

 humerus. 



Action. This is a muscle of considerable power and importance, being 

 specially instrumental in raising the limb from the ground and carrying it 

 forward in progression. Upon it chiefly depends that grand shoulder action 

 so much admired in our best harness horses. 



It is capable of acting in two directions: when the head is fixed it 

 raises and advances the fore-limb; when the fore-limb is fixed, as in a 

 standing posture, it draws the head to one side, or, acting with its fellow 

 on the opposite side, it pulls it downward. 



