740
UNIT 4
Maintenance of the Body
19
Table 19.11
Veins of the Upper Limbs and Thorax
Axillary
vein
Subclavian
vein
External
jugular vein
Internal
jugular vein
Brachiocephalic
veins
Superior
vena cava
Accessory
hemiazygos
vein
Brachial
vein
Median
cubital
vein
Hemiazygos
vein
Ulnar
vein
Radial
vein
Deep venous
palmar arch
Metacarpal veins
Superficial venous
palmar arch
Digital veins
(a) Schematic flowchart
Right and left posterior
intercostal veins
Azygos
vein
Basilic
vein
Cephalic
vein
Median
antebrachial
vein
Te deep veins of the upper limbs follow the paths of their com-
panion arteries and have the same names
(Figure 19.28a)
.
However, except for the largest, most are paired veins that flank
their artery. Te superficial veins of the upper limbs are larger
than the deep veins and are easily seen just beneath the skin.
Te median cubital vein, crossing the anterior aspect of the el-
bow, is commonly used to obtain blood samples or administer
intravenous medications.
Blood draining from the mammary glands and the first two
to three intercostal spaces enters the
brachiocephalic veins
.
However, the vast majority of thoracic tissues and the thorax
wall are drained by a complex network of veins called the
azy-
gos system
(az
9
ĭ-gos). Te branching nature of the azygos sys-
tem provides a collateral circulation for draining the abdominal
wall and other areas served by the inferior vena cava, and there
are numerous anastomoses between the azygos system and the
inferior vena cava.
Description and Areas Drained
Deep Veins of the Upper Limbs
Te most distal deep veins of the upper limb are the radial and
ulnar veins. Te
deep
and
superficial venous
palmar arches
of the hand empty into the
radial
and
ulnar veins
of the fore-
arm, which then unite to form the
brachial vein
of the arm. As
the brachial vein enters the axilla, it becomes the
axillary vein
,
which becomes the
subclavian vein
at the level of the first rib.
Superficial Veins of the Upper Limbs
Te superficial venous system begins with the
dorsal venous net-
work
(not illustrated), a plexus of superficial veins in the dorsum
of the hand. In the distal forearm, this plexus drains into two
major superficial veins—the cephalic and basilic veins—which
anastomose frequently as they course upward (Figure 19.28b).
Te
cephalic vein
bends around the radius as it travels supe-
riorly and then continues up the lateral superficial aspect of
the arm to the shoulder, where it runs in the groove between
the deltoid and pectoralis muscles to join the axillary vein. Te
basilic vein
courses along the posteromedial aspect of the fore-
arm, crosses the elbow, and then joins the brachial vein in the
axilla, forming the axillary vein. At the anterior aspect of the
elbow, the
median cubital vein
connects the basilic and cephalic
veins. Te
median antebrachial vein
lies between the radial and
ulnar veins in the forearm and terminates (variably) at the elbow
by entering either the basilic or the cephalic vein.
The Azygos System
Te azygos system consists of the following vessels, which flank
the vertebral column laterally.
Azygos vein.
Located against the right side of the vertebral
column, the
azygos vein
(
azygos
5
unpaired) originates in the
abdomen, from the
right ascending lumbar vein
that drains
most of the right abdominal cavity wall and from the
right pos-
terior intercostal veins
(except the first) that drain the chest
muscles. At the ±
4
level, it arches over the great vessels that run
to the right lung and empties into the superior vena cava.
Figure 19.28
Veins of the thorax and right upper limb.
For
clarity, the abundant branching and anastomoses of the superficial
veins are not shown.
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