19
Table 19.4
The Aorta and Major Arteries of the Systemic Circulation
Diaphragm
R. vertebral
L. vertebral
R. axillary
Arteries of
R. upper
limb
Visceral branches
Parietal branches
Visceral branches
Parietal branches
L. ventricle of heart
L. axillary
Aortic arch
Arteries of R. lower limb
(a) Schematic flowchart
Arteries of L. lower limb
Arteries of
L. upper
limb
R. external
carotid artery
R. internal
carotid artery
L. external
carotid artery
L. internal
carotid artery
R. common carotid
– right side of head and neck
L. common carotid
– left side of head and neck
R. subclavian
– neck and
R. upper limb
Brachiocephalic
– head, neck, and
R. upper limb
L. subclavian
– neck and L.
upper limb
Ascending aorta
– L. ventricle to sternal angle
L. and R. coronary
arteries
Thoracic aorta T
5
–T
12
(diaphragm)
Mediastinal
– posterior
media-
stinum
Esophageal
– esophagus
Bronchial
– lungs and
bronchi
Pericardial
– pericardium
Posterior intercostals
– intercostal muscles, spinal
cord, vertebrae, pleurae, skin
Superior phrenics
– posterior and superior
diaphragm
Abdominal aorta T
12
(diaphragm)–L
4
Gonadal
– testes or
ovaries
Suprarenal
– adrenal
glands
and
Renal
– kidneys
Superior
and inferior
mesenterics
– small
intestine
– colon
Celiac trunk
– liver
– gallbladder
– spleen
– stomach
– esophagus
– duodenum
Inferior phrenics
– inferior diaphragm
Lumbars
– posterior
abdominal
wall
Median sacral
– sacrum
– coccyx
L. common iliac
– pelvis and L. lower limb
R. common iliac
– pelvis and R. lower limb
Figure 19.21a
diagrams the distribution of the aorta and ma-
jor arteries of the systemic circulation in flowchart form, and
Figure 19.21b illustrates them. See Tables 19.5 through 19.8 for
fine points about the vessels arising from the aorta.
±e
aorta
is the largest artery in the body. In adults, the aorta
(a-or
9
tah) is approximately the size of a garden hose where it issues
from the le² ventricle of the heart. Its internal diameter is 2.5 cm,
and its wall is about 2 mm thick. It decreases in size slightly as it
runs to its terminus. ±e aortic valve guards the base of the aorta
and prevents backflow of blood during diastole. Opposite each
aortic valve cusp is an
aortic sinus
, which contains baroreceptors
important in reflex regulation of blood pressure.
Different portions of the aorta are named according to shape or
location. ±e first portion, the
ascending aorta
, runs posteriorly
and to the right of the pulmonary trunk. It persists for only about
5 cm before curving to the le² as the aortic arch. ±e only branches
of the ascending aorta are the
right
and
lef coronary arteries
,
which supply the myocardium. ±e
aortic arch
, deep to the ster-
num, begins and ends at the sternal angle (T
4
level). Its three major
branches (R to L) are: (1) the
brachiocephalic trunk
(bra
9
ke-o-sĕ-
fal
0
ik; “armhead”), which passes superiorly under the right ster-
noclavicular joint and branches into the
right common carotid
artery
(kah-rot
9
id) and the
right subclavian artery
, (2) the
lef
common carotid artery
, and (3) the
lef subclavian artery
. ±ese
three vessels provide the arterial supply of the head, neck, upper
limbs, and part of the thorax wall.
±e
descending aorta
runs along the anterior spine. Called
the
thoracic aorta
from T
5
to T
12
, it sends off numerous small
arteries to the thorax wall and viscera before piercing the dia-
phragm. As it enters the abdominal cavity, it becomes the
ab-
dominal aorta
. ±is portion supplies the abdominal walls and
viscera and ends at the L
4
level, where it splits into the
right
and
lef common iliac arteries
, which supply the pelvis and lower
limbs.
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