It should be remembered that most of the branches which spring from
the great artery and vein are double—that is, each right branch has a
corresponding one at the left side—so that there are, for instance,
the right and the left carotid arteries, the right and the left
jugular veins, etc.
From the arch of the aorta are sent off those arteries which are
distributed to the head and arms. The principal ones among these are
named as follows:
_g_, The carotid artery, which ascends in the side of the neck, and
divides into the temporal artery, _h_, which is distributed in the
temple, and the facial artery, _i_, which supplies the face; and also
sends a branch, called the internal carotid, to the parts within the
skull.
_j_, The sub-clavian artery, lying beneath the clavicle or
collar-bone. That part of the continuation of this artery which
passes through the axilla or arm-pit is called the axillary artery,
_k_; that which lies in the upper arm, the brachial artery, _l_; and
in the fore-arm it divides into the radial and ulnar arteries, _m_,
_n_, which are distributed to the hand and fingers in the manner
indicated in the plate.
The principal branches of the descending aorta are named as follows:
The iliac artery, _o_, on passing into the thigh becomes the femoral
artery, _p_, and in the leg divides into the tibial and peroneal
arteries, _q_, _r_, which form numerous branches for the supply of
the leg and foot.
Before dividing into the iliac arteries, the descending aorta gives
off several important branches, as the cœliac artery, from which the
stomach and liver are supplied; the renal artery, which goes to the
kidneys, and the mesenteric artery, to the intestines; besides many
other sub-divisions in various parts of its course.
The branches of the vena cava generally accompany those of the aorta
in their distribution, as shown in the figure, and are often called
by the same names. The principal divisions of the superior vena cava
are: The jugular vein, _s_, which accompanies the carotid artery the
sub-clavian vein, _t_, which accompanies the artery of the same name,
and receives the blood from the arm and hand.
The inferior vena cava, like the aorta, divides into two great
branches, the iliac veins, _u_, the sub-divisions of which accompany
those of the arteries, and are called by the same names. The manner
in which the superficial veins ramify and anastomose with each other
is shown on the upper and lower extremity of the left side.