482 
ANATOMY OF TIIE HORSE ; 
a n tea-spin at us .—( Super-acromio-trochiterius.J 
Situation. —Occupying theybss# antea spinata scapula. 
Figure. —Approaching that of an extended triangle; having its 
base thick and turned downwards, its apex thin and rounded 
off. y , ; ' t |H 
Attachment. —Superiorly, to the surface of the fossa antea 
spinata; also to the spine and anterior costa of the scapula: in¬ 
teriorly, to the summits of the greater and lesser tubercles of the 
humerus, and to the capsular ligament of the shoulder joint. 
Relations.- —Externally, with the panniculus and skin; inter¬ 
nally, with the bone: anteriorly and superiorly, with the levator 
humeri and pectoralis parvus; posteriorly and inferiorly, with 
the next muscle : below, with the shoulder joint. 
Direction. —Oblique ; from above downward, and from be¬ 
hind forward. 
Structure. —Surface aponeurotic, with a tendinous intersection 
through its middle. 
O m 
Attachment. —Tendinous and fleshy: inferiorly, the fleshy part 
presents two terminations, united by an intervening expansion of 
tendon, which fills up the interspace between them. At the point 
of the shoulder is sent off a tendinous expansion, between which 
and the tendon of the biceps is interposed a bursa mucosa. 
Action. —To extend the humerus upon the scapula; at least, 
to approach that bone to the straight line, 
postea-spinatus.— (Sub-acromio-trochiterius.) 
Situation. —Occupying the fossa postea spinata. 
Figure. —Triangular; flattened: broader, but not so thick in 
substance as the preceding muscle. 
Attachment. —Superiorly, to the surface of the fossa postea 
spinata, and to the spine of the bone ; inferiorly, to the outer side 
of the greater tubercle of the humerus, to a bony ridge extending 
down from it, and to the capsular ligament of the shoulder 
joint. 
Relations. —On the outer side, with the panniculus and skin, 
and also (superiorly) with the trapezius; anteriorly, with the 
foregoing muscle; posteriorly, with the teres minor and triceps; 
inferiorly, with the shoulder joint. 
Structure .—Superior attachments, aponeurotic as well as 
fleshy. Its middle presents several broad tendinous intersections, 
from the principal of which originates a flattened tendon, fixing 
the muscle to the tubercle. Below the tendon, is the tendinous 
and fleshy portion fixed to the ridge; and still lower is a distinct 
and separate fasciculus, proceeding to a small tubercle upon the 
