The Aorta and Its Major Branches - Amazon S3

[Pages:9]The Aorta and Its Major Branches

The aorta is the biggest artery in the body, with a diameter of approximately 3 cm (1 in.). All systemic arteries branch off the aorta. The aorta has four major segments: ascending aorta, arch of the aorta (or aortic arch), thoracic aorta, and abdominal aorta. Arteries that branch off each section of the aorta divide into smaller arteries that supply different organs. These arteries then divide into arterioles within the organs, and finally into capillaries that supply all systemic tissues accept the alveoli of the lungs.

The Ascending Aorta

The ascending aorta, which is approximately 5 cm (2 in.) long, is the first section of the aorta. It begins at the aortic valve, at the upper part of the base of the left ventricle. It has three dilations called aortic sinuses. The right and left coronary arteries originate from the right and left aortic sinuses. The posterior interventricular branch of the right coronary artery supplies the right and left ventricles. The right ventricle also receives blood from the second branch of the right coronary artery, the marginal branch. The left coronary artery has two branches: the anterior interventricular branch (left anterior descending branch), which supplies both ventricles, and the circumflex branch, which supplies the left ventricle and left atrium.

The Arch of the Aorta

The ascending aorta curves to the left and becomes the arch of the aorta, which is about 4?5 cm (2 in.) long. It runs downward and ends in front of the border between the fourth and fifth thoracic vertebrae. The arch of the aorta gives rise to three major branches: the brachiocephalic trunk, left common carotid artery, and left subclavian artery.

Branches of the Arch of the Aorta

Branch

Area Supplied

Description

Brachiocephalic trunk

Right upper limb, head, neck

Brachiocephalic

trunk (brachiocephalic

artery) is the largest branch of the aortic arch;

Gives rise to the right subclavian

arteryand right common carotid artery

Right subclavian artery

Right upper limb, brain, spinal cord, neck, shoulder, thoracic viscera and wall, scapular muscles

Runs from the brachiocephalic trunk and to the first rib before passing into the armpit (axilla)

Internal thoracic artery

Anterior thoracic wall, mediastinum structures

The internal thoracic artery branches from the first part of the subclavian artery; Ends at the sixth intercostal space; Used to create the bypass for single coronary artery bypass grafting

Vertebral artery

Posterior part of The right vertebral artery branches off from the

brain

right subclavian artery and passes through the

foramen magnum to reach the inferior surface

of the brain; Joins with the left vertebral artery

to form the basilar artery, branches of which

Branch

Area Supplied

Description

supply the cerebellum and pons of the brain, and the inner ear

Axillary artery

Shoulder, thoracic

and

scapular

muscles, humerus

The axillary artery is the part of the subclavian artery that passes into the armpit; The same vessel has different names as it passes through different areas of the body

Brachial artery Upper limb

The axillary artery becomes the brachial artery in the arm, where it is easy measure BP; To control bleeding, the brachial artery should be compressed near the middle of the arm

Radial artery

Radial (lateral) aspect of forearm, wrist, hand

The radial artery is a direct continuation of the brachial artery very near the skin surface at the wrist, where the radial pulse is typically measured

Ulnar artery

Ulnar (medial) aspect of forearm, wrist, hand

The ulnar artery is the larger of the two brachial artery branches; Reconnects with the smaller branch (the radial artery), in the palm, creating the superficial palmar arch and the deep palmar arch

Superficial palmar arch

Branches supply palm and fingers

Lies over the flexor tendons of the fingers and extends to the palm; Gives rise to the common palmar digital arteries that perfuse the palm, each of which divides into a pair of proper palmar digital arteries that perfuse the fingers

Deep arch

palmar

Branches supply the palm and fingers

Lies below the flexor tendons of the fingers and extends to the palm; Gives rise to palmar metacarpal arteries that perfuse the palm and join with the common palmar digital arteries

Right common Head and neck Begins where the brachiocephalic trunk divides

carotid artery (right side)

into its two branches; Divides into the right

external and right internal carotid arteries;

Often used to measure the pulse (at the side of

the neck), for example, when exercising or

administering cardiopulmonary resuscitation

External carotid Face, scalp, neck artery

Near the temporomandibular joint, the external carotid artery divides into the superficial

Branch

Area Supplied

Description

temporal and maxillary arteries; Used to detect the carotid pulse

Internal artery

carotid

Orbital structures

(including the

eyeball),

ear,

cerebrum, pituitary

gland, external

nose

Branches of the internal carotid artery:

the anterior cerebral arteries supply parts of

the frontal and parietal lobes; Branches merge

with branches of the basilar artery--

the posterior cerebral arteries(that supply the

occipital lobes)--to form the cerebral arterial

circle(circle of Willis) at the base of the

brain; Posterior

communicating

arteries connect the posterior cerebral arteries

with the internal carotid arteries; Anterior

communicating arteriesconnect the anterior

cerebral arteries; Cerebral arterial circle (which

also includes the internal carotid arteries)

equalizes BP in the brain and keeps blood

flowing to the brain if other arteries are

damaged

Left common Head and neck The left common carotid artery branches from

carotid artery (left side)

the arch of the aorta and divides into branches

with the same names as branches of the right

common carotid artery

Left subclavian Left upper limb artery

The left subclavian artery branches from the arch of the aorta; Its branches and their names are similar to those of the right subclavian artery

The Thoracic Aorta

As the aorta continues its descent, it passes through the aortic hiatus, an opening in the diaphragm. The part of the aorta between the arch of the aorta and the diaphragm is called the thoracic aorta. It is approximately 20 cm (8 in.) long and starts at the border between the fourth and fifth thoracic vertebrae. The thoracic aorta gives rise to a number of small arteries. The visceral branches supply the viscera, and the parietal branches supply the body wall structures of the thorax.

Branches of the Thoracic Aorta: Visceral

Branch Pericardial arteries Bronchial arteries

Esophageal arteries Mediastinal arteries

Area Supplied

Description

Pericardium

Two or three of these tiny pericardial arteries perfuse the pericardium

Pleurae,

bronchial

tubes, bronchial lymph

nodes, esophagus

Right bronchial artery branches from the third posterior intercostal artery; Two left bronchial arteries branch from the thoracic aorta

Esophagus

Four or five esophageal arteries perfuse the esophagus

Mediastinum structures Numerous small mediastinal arteries

Branches of the Thoracic Aorta: Parietal

Branch

Area Supplied

Description

Branch Posterior intercostal arteries

Subcostal arteries

Superior phrenic arteries

Area Supplied

Description

Intercostal, pectoralis major and minor, and serratus anterior muscles; overlying subcutaneous tissue and skin; mammary glands; vertebrae, meninges, spinal cord

Nine pairs of intercostal arteries

posterior

Same as the posterior intercostal arteries

The subcostal arteries derive their name from their location below the rib cage (costal, rib area)

Superior and posterior aspects of The small superior phrenic

diaphragm

arteries arise from the lower

part of the thoracic aorta

The Abdominal Aorta

The abdominal aorta is the part of the aorta between the diaphragm and its bifurcation (division into two branches) into the two common iliac arteries at the level of the fourth lumbar vertebra. The abdominal aorta is about 13 cm (5.1 in.) long. Like the thoracic aorta, the abdominal aorta gives off visceral and parietal branches.

Branches of the Abdominal Aorta: Unpaired Visceral Branches

Branch

Area Supplied Description

Celiac trunk

After emerging from the abdominal aorta, the celiac trunk divides into the left gastric artery, splenic artery, and common hepatic artery

Left gastric Stomach,

artery

esophagus

Smallest of the three branches of the celiac trunk

Splenic artery

Branches supply pancreas, stomach, greater omentum

Largest branch of the celiac trunk; Three branches: pancreatic artery(supplies the pancreas), left gastroepiploic artery (stomach and greater omentum), short gastric artery (stomach)

Common hepatic artery

Branches supply

liver,

gall

bladder,

stomach,

duodenum,

pancreas,

greater

omentum

Intermediate-sized branch of the celiac trunk; Three branches: proper hepatic artery (supplies the liver, stomach, and gall bladder), right gastric artery (stomach), gastroduodenal artery (stomach, greater omentum, duodenum, and pancreas)

Superior Branches supply The superior mesenteric artery runs between the layers

Branch

Area Supplied Description

mesenteric artery

duodenum, pancreas, parts of small and large intestines

of

mesentery;

Five

branches: inferior

pancreaticoduodenal artery (supplies the duodenum

and pancreas), jejunal artery (jejunum of small

intestine),ileal

artery (ileum

of

small

intestine), ileocolic artery (ascending colon of large

intestine), middle colic artery (transverse colon of large

intestine)

Inferior mesenteric artery

Branches supply parts of large intestine

The inferior mesenteric artery has three branches: left colic artery(supplies transverse and descending colons of large intestine), sigmoid arteries (sigmoid and descending colons of large intestine), superior rectal artery (rectum)

Branches of the Abdominal Aorta: Paired Visceral Branches

Branch Suprarenal arteries

Renal arteries Gonadal arteries

Area Supplied

Description

Adrenal glands

Only the middle pair of suprarenal arteries arises from the abdominal aorta; Superior pair arises from the inferior phrenic artery; Inferior pair arises from the renal arteries

Kidneys,

adrenal Right renal artery is longer than the left

glands, ureters

Ureters,

ovaries,

fallopian

tubes

(females);

testes,

epididymis (males)

In males, the gonadal arteries are called the testicular arteries; In females, they are called the ovarian arteries(which are much shorter than the testicular arteries)

Branches of the Abdominal Aorta: Unpaired Parietal Branch

Branch

Median sacral artery

Area Supplied

Sacrum, coccyx

Description

The median sacral artery originates in the posterior part of the abdominal aorta, about 1cm above the bifurcation into the right and left common iliac arteries

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