72 CTCLOPEDIA OF LIVE STOCK AND COMPLETE STOCK DOCTOR, 



into two parts to permit the passage of the side dihitor of the nostril (/), 

 one branch passing straight to the corners of the mouth : its use being 

 to raise it. The other branch expanding under the side dilator, not only 

 assists in dilating the nostril, but also in lifting the upper lip. 



The under lip is drawn back by the narrow muscle (/), which is inserted 

 into the lip below the angle of the mouth. Passing along the side of the 

 jaw, it disappears under the masseter or cheek muscle (a). 



Muscles of the Neck. — One of the principal muscles of the neck rises 

 from the transverse processes of the first four or five dorsal vertebne, 

 page 54 (3), and also from the five lower bones of the neck (2), same 

 page. The fibers from these two points, uniting form one large muscle, 

 which, in fact, makes up the principal lower part of the neck, and which, 

 diminishing in size as it passes towards the head, terminates in a tendon 

 inserted in the {occipital) bone covering the back of the head. See page 

 61 (c). Immediately above is the muscle splenius (k,) page 71 . It is 

 used for raising the head. This muscle arises from the entire length of 

 a strong and elastic ligament {ligamentum nuchce), having its origin 

 from the back of the occipital l)one, to which it is attached immediately 

 below the crest. At first cord-like, it passes over the first joint of the 

 neck and adheres strongly to the second bone of the neck, on which the 

 principal weight of the head is thrown ; it thence proceeds backward un 

 to its termination on the elevated spinous processes of the bones of the 

 Avithcrs. Thus the withers have to support the entire weight of the head 

 and neck, when held in their usual position. 



To return to the fiplenius. It is inserted directly into all the bones of 

 the neck except the first, but having with this and the temporal bone, a sep- 

 arate and distinct connection. To its form and development, the muscu- 

 larity and beauty of the neck are chiefly due. The tiiick crest and mas- 

 sive neck of the stallion, is princij^ally due to its great development. If 

 overloaded with cellular tissue or fat, the neck mil be clumsy. These 

 facts cannot be too carefully borne in mind, for whatever the condition or 

 breed of the horse it is this muscle which gives character to the neck. 



Behind the splenius, and extending along the upper margin of the neck, 

 is a muscle (levator angidi scapulae') (I). Inserted in the back of the 

 head, and attached to the first four bones of the neck and to 

 the great ligament, it descends to the shoulder, out of sight. It.s 

 action is reciprocal on the neck and shoulder, according as one or the 

 other may be fixed at the time. 



Muscles of the Front of the Neck. — On page 71(fig. 2, m.) immediately 

 below the head at its junction with the neck, its upper extremity, con- 

 spicuous, is the muscle hyoideus. It is attached to the hyoid bone of 



