originates in the dorsal
abdominal wall and ascends through the mediastinum on the
right side of the vertebral column to join the superior vena
cava. It drains most of the muscular tissue in the abdominal
and thoracic walls.
Tributaries of the azygos vein include the
on the right side, which drain the intercos-
tal spaces, and the
inferior hemiazygos veins,
which receive blood from the posterior intercostal veins
on the left. The right and left
ascending lumbar veins,
tributaries that include vessels from the lumbar and sacral
regions, also connect to the azygos system.
Veins from the Abdominal Viscera
Veins carry blood directly to the atria of the heart, except
those that drain the abdominal viscera
(f g. 15.55)
originate in the capillary networks of the stomach, intes-
tines, pancreas, and spleen and carry blood from these
organs through a
to the liver
(f g. 15.56)
. There the blood enters capillary-like
˘-soidz). This unique venous path-
way is called the
hepatic portal system.
The tributaries of the hepatic portal vein include the fol-
1. Right and left
from the stomach.
Superior mesenteric vein
from the small intestine,
ascending colon, and transverse colon.
passes along the back of the
forearm on the ulnar side for a distance and then curves for-
ward to the anterior surface below the elbow. It continues
ascending on the medial side until it reaches the middle of
the arm. There it deeply penetrates the tissues and joins the
As the basilic and brachial veins merge, they
courses upward on the lat-
eral side of the upper limb from the hand to the shoulder. In
the shoulder, it pierces the tissues and joins the axillary vein,
which beyond the axilla becomes the
In the bend of the elbow, a
median cubital vein
from the cephalic vein on the lateral side of the forearm to
the basilic vein on the medial side. This large vein is usually
visible. It is often used as a site for
when it is
necessary to remove a sample of blood for examination or to
add ﬂ uids to the blood.
Veins from the Abdominal and
Tributaries of the brachiocephalic and azygos veins drain
the abdominal and thoracic walls. For example, the
receives blood from the
internal thoracic vein,
which generally drains the tissues the internal thoracic artery
also empty into the brachio-
External jugular v.
Superior vena cava
Internal jugular v.
Superior hemiazygos v.
Posterior intercostal v.
Inferior hemiazygos v.
Veins that drain the thoracic wall. (
stands for vein,
stands for veins.)