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ANATOMY OF TIIE HORSE. 
process of the os hyoides: also, by a detached slender tendon, to 
the lower border of the thyroid cartilage. 
Relations. —Interiorly, with the sterno-maxillaris ; superiorly, 
with the trachea, and on the left side with the oesophagus like¬ 
wise : along its outer border, with the recurrrent nerve ; along its 
inner or mesian line, with its fellow. 
Structure .—Sternal end, tendinous and fleshy, and united in 
one belly; at the other end, there are two fleshy bellies ; and 
the three are connected opposite to the trachea, about the middle 
of the neck, by an intermediate, short, and slender tendon. 
Action. —To draw the os hyoides, and along with it the larynx, 
downwards and backwards. 
SUBSCAPULO-IIYOIDEU S. 
Situation .—Continued from the levator humeri, and spread 
over the antero-superior parts of the neck. 
Form. —A broad, thin, elongated band ; thicker and broader 
anteriorly than posteriorly. 
Attachment. —In connection with the levator humeri, to the 
inner surface of the scapula; anteriorly, to the middle of the body 
of the os hyoides. 
Relations. —Its course lies between the carotid artery and the 
jugular vein, between which it forms a fleshy partition ; having on 
its outer side, the sterno-maxillaris; on its inner, the sterno- 
thyro-hyoideus ; and at its anterior termination, becoming em¬ 
bedded between the submaxillary glands. 
Structure. —The scapular end consists of a thin flattened ten¬ 
don : the remaining part is fleshy. It forms altogether a sort of 
fleshy involucrum for the next muscle. 
Action. —It will draw the os hyoides downwards and back¬ 
wards. 
scalenus .— Costo-cervicalis. 
Situation. —Postero-inferior part of the neck. 
Form. —Pyramidal: base cut slantwise and turned down¬ 
wards. 
Attachment. —Posteriorly, to the middle of the first rib ; an¬ 
teriorly, to the bodies and transverse processes of the 5th and 6th 
cervical vertebrae. 
Relations. —Along its upper margin, with the transversalis 
colli; along its lower, with the sterno-maxillaris: on the outer 
side, with the levator humeri; on the inner, with the trachea; 
and on the left side also with the oesophagus. In the interspace 
between one scalenus and the other, on the carotid artery, par 
