172 



THE ANATOMY AND DISEASES OF 



the animal to his situation and use, has given to the cart-horse, that is seldom 

 blown, a confined nostril, and surrounded by much cellular substance, and a 

 thick skin ; and to the horse of more breeding, whose use consists in his speed 

 and his continuance, a wider nostril, and one much more flexible. 



The inhabitants of some countries were accustomed to slit the nostrils of 

 their horses, that they might be less distressed in the severe and long-continued 

 exertion of their speed. The Icelanders do so to the present day. There is no 

 necessity for this, for nature has made ample provision for all the ordinary and 

 even extraordinary exertion we can require from the horse* 



Some very powerful muscles proceed from different parts of the face to the 

 neighbourhood of the nostrils, in order to draw them back and dilate them. Four 

 of these are given in this cut, which is introduced to complete our present subject, 

 and which will be often referred to in the course of our work ; I, m, o, and jo, 

 are muscles employed for this purpose. 



THE MUSCLES, NERVES, AND BLOOD-VESSELS OF THE HEAD AND UPPER PART OF THE NECK. 



a The upper part of the ligament of the neck. 



b The levator humeri (elevator of the shoulder), arising from the tubercle of the occiput, the 

 mastoid (nipple-shaped) process of the temporal bone, and the transverse processes (cross 

 projections) of the four first bones of the neck, and the ligament of the neck, and going to 

 the muscles of the shoulders, and the upper bone of the arm : to draw forward the 

 shoulder and arm ; or turu the head and neck ; and, when the two levators act, to de- 

 press the head. 



c The tendon common to the complexus major (larger complicated), and splenius (splint- 

 like) : to the mastoid process of the temporal bone, to hold up the head, or, the muscles 

 on one side alone acting, to turn it. 



d The sterno-maxillaris (belonging to the breast-bone) and upper jaw, from the cartilage in 

 front of the chest to the angle of the lower jaw : to bend the head, or, if one only acts, 

 to bend it on one side. 



e The stylo-maxillaris^ from the styloid (pencil-shaped) or coracoid (beak-shaped) process of 

 the occiput, to the angle of the jaw : to pull the jaw backward and open it. 



/ The subscapulo hyoideus, from under the shoulder-blade, to the body of the os hyoides 

 (the bone at the root of the tongue formed like a Greek u, y) : to draw back that bone. 



y The masseter (chewing) ; a most powerful muscle, constituting the cheek of the horse : 

 from the upper jaw-bone into the rough surface round the angle of the lower : in con- 

 junction with the temporal muscle to close the mouth and chew the food. 



h The orbicularis (circular) surrounding the eye and closing the lids. 



i The zyyomaticus, from the zygoinatic arch and masseter to the corner of the mouth, to draw 

 back the angle of the mouth. 



fc The buccinator (trumpeter), from the inside of the mouth and cheeks, to the angle of the 

 mouth, to draw it back. 



