786 THE VASCULAR SYSTEM. 
cutaneous, lesser internal cutaneous, and ulnar nerves, and in the lower part with the 
median nerve. Two vena comites, one on each side, accompany the artery, and com- 
munications between these pass across the vessel. 
BRANCHES OF THE BRACHIAL ARTERY. 
(1) The superior profunda (a. profunda brachii) is a large branch which 
arises from the inner and back part of the brachial soon after its commencement. 
It runs downwards and outwards, with the musculo-spiral nerve, in the musculo- 
spiral groove, and divides at the back of the humerus into two terminal branches, 
the anterior and the posterior. Not infrequently this division takes place at a 
higher level, and the artery appears double. The anterior terminal branch 
accompanies the musculo- spiral nerve through the external intermuscular septum, 
and descends between the supinator longus and the brachialis anticus to the front 
of the external condyle, where it anastomoses with the radial recurrent artery. 
The posterior terminal branch descends behind the external intermuscular septum, 
and anastomoses behind the external condyle with the posterior interosseous 
recurrent artery and with the anastomotic artery. 
Whilst they are lying at the back of the humerus one of the terminal branches 
vives off—(a) a slender twig, which descends in the substance of the internal head 
of the triceps to the back of the elbow, where it anastomoses with the anastomotic 
artery ; (b) a nutrient branch, which enters a foramen on the posterior surface of the 
humerus; and (c) an ascending braneh, which anastomoses with the descending 
braneh of the posterior circumflex artery. 
(2) Muscular branches are given to the biceps, coraco-brachialis, brachialis 
anticus, triceps, and pronator radii teres. 
(3) Nutrient.—A small artery which arises from the middle of the brachial and 
enters the nutrient foramen on the inner side of the shaft of the humerus. 
(4) The inferior profunda (a. collateralis ulnaris superior) is smaller 
than the superior profunda, with which it sometimes rises by a common trunk ; 
usually, however, it springs from the imner and back part of the middle of the 
brachial. {t runs downwards and backwards, with the ulnar nerve, through the 
internal intermuscular septum, and then, descending more vertically, reaches the 
back of the internal condyle of the humerus, where it terminates by anastomosing 
with the posterior ulnar recurrent and anastomotic arteries. 
(5) The anastomotic (a. collateralis ulnaris inferior) rises from the iner 
side of the brachial artery about two inches (50 mm.) above its termination. 
It runs inwards behind the median nerve and in front of the brachialis anticus, it 
then pierces the internal intermuscular septum, and turns outwards between the 
inner head of the triceps and the posterior surface of the bone to the external con- 
dyle. It supplies the adjacent muscles and anastomoses, in front of the internal 
condyle, with the anterior ulnar recurrent, behind the internal condyle with the 
posterior ulnar recurrent and the inferior profunda, at the middle of the back of the 
humerus with a branch of the superior profunda, and behind the external condyle 
with the posterior terminal branch of the superior profunda and the posterior 
interosseous recurrent artery. 
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THE RADIAL ARTERY. 
The radial artery (a. radialis, Figs. 563, 564, and 565) is the smaller of the 
two terminal branches of the brachial arter y but it is the more direct continuation 
of the parent trunk. It commences in the ante-cubital fossa opposite the neck of 
the radius, and terminates in the palm of the hand, by anastomosing with the - 
deep branch of the ulnar artery, and thus completing the deep palmar arch. 
The trunk is divisible into three parts. 
The first part les on the front of the forearm. It runs downwards and some- 
what outwards to the apex of the styloid process of the radius. The second part — 
curves round the outer side of the wrist and across the back of the trapezium to 
reach the proximal end of the first imterosseous space. The third part passes 
