MYOLOGY. 65 
the inferior angle of the scapula below the infra-spinatus, and is inserted 
into the inner or posterior edge of the bicipital groove, below the tendon 
of the latissimus dorsi. It rotates the humerus inwards, adducts and draws 
it downwards and backwards; it also draws forwards the inferior angle of 
the scapula. 
The coraco-brachialis arises from the point of the coracoid process and 
from the tendon of ‘the short head of the biceps; descending obliquely for- 
wards, it is inserted into the’ inner side of the humerus, a little below the 
middle, and into the ridge leading to the internal condyle by an aponeurosis. It 
serves to adduct, raise, and draw forward the arm; also to rotate it outwards. 
Biceps is situated along the fore part of the humerus, and consists of twe 
portions superiorly, the external or long, and the internal or short. The 
internal arises from the coracoid process between the coraco-brachialis and 
the triangular ligament ; the external or long head arises by a long tendon 
from the upper part of the glenoid cavity of the scapula; the two uniting 
about the middle of the humerus in a large fleshy belly, which ends in a flat 
tendon to be inserted into the back part of the tubercle of the radius. A 
process from the anterior and outer border of this tendon, called the semi- 
lunar fascia; passes to the internal condyle and to the aponeurosis of the 
forearm.’ Its use is to flex the forearm and stretch its fasciz; also to 
abduct and raise the arm. 
© Brachialis anticus or externus arises from the centre of the humerus by 
two fleshy slips, one on either side of the insertion of the deltoid; it is 
inserted by a strong tendon into the coronoid process of the ulna and into 
a rough surface on this bone beneath that process. Use: to flex the fore- 
arm, also to strengthen the articulation when extended. 
« Triceps extensor cubiti covers the back of the humerus, and extends from 
the scapula to the olecranon; it consists superiorly of three portions, the 
middle or long, the second or external, and the third or internal or short 
head (brachialis internus or. posticus). The long or middle head arises 
from the lower part of the neck of the scapula; the second arises immie- 
diately below the insertion of the teres minor from and behind a ridge on 
the outer side of the humerus, commencing below the great tuberosity and 
leading down to the external condyle; the third or short head arises on the 
inside of the humerus above its centre. ‘These three portions unite above 
the middle of the arm, and descending, terminate in a broad tendon of two 
lamine, a superficial and a deep; the former is continued into the fasciz 
on the back part of the forearm, the latter is inserted into the posterior 
border but not the point of the olecranon. Use: to extend the forearm on 
the arm, by its long portion to carry the arm backwards, and in some cases 
to abduct it. The triceps is thus the great extensor of the elbow joint, 
while the biceps and brachialis anticus are the antagonist flexors. The 
flexors thus predominate over the extensors, the contrary being the case in 
the knee joint. 
2. MUSCLES OF THE FoREARM. As these muscles are very numerous, they 
will be most conveniently described by classing them according to their 
situations and use. One set is employed in bending the forearm, wrist, 
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