62 
ANATOMY OF THE HORSE. 
fourth cervical vertebra laterally, from the ligamentum nuchse 
and faschia covering the side of the neck; interiorly and poste¬ 
riorly, loosely to the head of the humerus, to the scapular faschia, 
to the muscles about the point of the shoulder, and ultimately to 
a ridge upon the body of the humerus, which arises from its 
greater tubercle. 
Relations —The jugular vein runs along its antero-inferior 
border, and is covered by it for three-fourths of its length down¬ 
wards. The subcutaneous branches of the cervical nerves pierce 
its substance and ramify upon its surface. Superiorly and pos¬ 
teriorly, it Ts opposed to the splenius; inferiorly and anteriorly, 
to the sterno-maxillaris; on its outer side, to the panniculus; on 
its inner side, to the rectus capitis anticus major, and to the sca¬ 
lenus. Its antero-inferior margin is thin and expanded, and 
clips inward, forming a thin fleshy partition between the carotid 
artery and jugular vein. 
Direction. —Longitudinal: sloping with the neck. 
Structure. —Anteriorly it is split into two portions, both thin 
and aponeurotic at their extremities. Its middle part is thick 
and entirely fleshy, but upon the arm becomes aponeurotic. 
Action. —To raise the shoulder and arm, and at the same time 
draw them forwards: or, these parts being fixed, to turn the 
neck, and head also, to one side; or, should Loth act, under such 
circumstances, the head will be depressed. 
Remark. —Professor Girard considers the fleshy expansion be¬ 
tween the artery and vein as a distinct muscle, and names it the 
subscapulo-hyoideus: and so it would seem most natural to 
regard it. 
2.—LATERAL CERVICAL REGION. 
splenius.— Cervico-mastoideus. 
• * 
Situation .—-Occupying the whole of the superior and lateral 
parts of the neck. 
Form .—Irregularly quadrangular; The supero-lateral being 
acute and extended : thick in substance and flattened upon the 
sides. 
Attachment. —Superiorly, to the ligamentum colli, reaching as 
far forward as the occiput, and as far backward as the fourth or 
fifth dorsal spine : inferiorly, to the transverse processes of all the 
cervical vertebrse, and to the mastoid process of the temporal 
bone. 
Relations. —Internally, with the aponeurosis of the pannicu¬ 
lus upon the side of the neck, with part of the levator humeri 
near the head, and with part of the serratus magnus near the 
