543 
ANATOMY OF THE HORSE. 
ancon e us.— Epicondylo-olecranius. 
Situation .—Occupying the hollow space behind, between the 
condyles of the humerus. 
Form .—Short, thick, triangular: base turned downward. 
Attachment .— Superiorly, to the infero-posterior parts of the 
body of the humerus: inferiorly, to the antero-external part of 
the olecranon and to the capsular ligament of the elbow joint. 
Relations .—Posteriorly, with the triceps; anteriorly, with the 
humbrus and the elbow joint. 
Action. —To assist the triceps in the extension of the elbow 
joint; and to prevent the capsular ligament from being pinched 
between the bones during that action. 
MUSCLES OF THE ARM AND FORE LEG. 
' • r 
These muscles may be classed into two sets: those which 
extend the leg; viz. the Extensors; and those that bend it; viz. 
the Flexors . They are both included within and firmly bound 
by the brachial faschia; from which some fibres belonging to the 
superficial muscles derive their origin. 
1.—ANTERIOR ERACHIO-C RURAL REGION. 
This region includes all the extensors. The mass of them 
forms the prominence so perceptible upon the front of a well- 
formed arm. Collectively considered, they possess much less 
power than the flexors. 
extensor metacarpi magnus. — Epitrochlo-premetacarpeus. 
Situation .—Fore part of the arm. 
Figure. —Pyramidal: rounded superiorly ; flattened inferiorly. 
Attachment. —Superiorly, to the outer and fore parts of the 
external condyle of the humerus; and also to the capsular liga¬ 
ment: inferiorly, to the antero-superior part of the os metacarpi 
magnum. 
Relations. —Anteriorly, with the faschia and skin; posteriorly, 
with the radius: externally, with the extensores pedis et obii- 
quus; internally, with the flexor brachii and the skin. The su¬ 
perficial brachial vein ascends along its inner side. 
Structure .—Its superior attachment is principally fleshy; 
though it possesses some tendinous fibres which are inseparably 
united with the tendon of the next (to be described) muscle. 
The middle part has but few tendinous intersections. The sur¬ 
faces are partly aponeurotic. Below' the middle of its length 
arises a tendon, round at its origin, but gradually growing flat, 
