Large veins and arteries of the thorax pdf - Thorax

Basic Anatomy

arterial end

venous end

dorsal mesocardium

loss of dorsal mesocardium

serous

pericardium

visceral

layers of serous

pericardium

fibrous

pericardium

pericardial cavity

transverse sinus

superior vena cava

pulmonary veins

pulmonary trunk

aorta

inferior vena

cava

fibrous pericardium

transverse sinus

oblique sinus

endocardial tube

FIGURE 3.43

The development of the endocardial tube in relation to the pericardial cavity.

heart (Fig. 3.36). The vena azygos joins the posterior aspect

3.48). It passes downward to end in the right atrium of the

the union of the two brachiocephalic veins (Figs. 3.32 and

the head and neck and both upper limbs and is formed by

The superior vena cava contains all the venous blood from

Superior Vena Cava

the superior vena cava (Fig. 3.48).

aortic arch. It joins the right brachiocephalic vein to form

manubrium sterni and in front of the large branches of the

It passes obliquely downward and to the right behind the

has a similar origin (Figs. 3.30 and 3.32).

chiocephalic vein

left bra

internal jugular veins (Figs. 3.15 and 3.48). The

the neck by the union of the right subclavian and the right

is formed at the root of

right brachiocephalic vein

The

Brachiocephalic Veins

Large Veins of the Thorax

include large ventricular septal defect; stenosis of the pulmonary

the abdominal veins and increasing the systemic arterial resis

severe untreated abnormalities die. Once the diagnosis has been

congenital cyanosis and considerably limit activity; patients with

the high blood pressure in the right ventricle. The defects cause

ity only); and severe hypertrophy of the right ventricle, because of

ventricular septal defect (instead of from the left ventricular cav

or at the pulmonary valve; exit of the aorta immediately above the

trunk, which can occur at the infundibulum of the right ventricle

made, most children can be successfully treated surgically.

Most children find that assuming the squatting position after

physical activity relieves their breathlessness. This happens

because squatting reduces the venous return by compressing

tance by kinking the femoral and popliteal arteries in the legs;

both these mechanisms tend to decrease the right-to-left shunt

through the ventricular septal defect and improve the pulmonary

circulation.

CHAPTER 3

The Thorax: Part II—The Thoracic Cavity

arteries of

pharyngeal arches

pericardial

cavity

serous

pericardium

fibrous

pericardium

umbilical vein

vitelline vein

common cardinal vein

aortic sac

truncus arteriosus
(distal part of
bulbus cordis)

bulbus cordis

ventricle

atrium

sinus venosus

horn of sinus venosus

FIGURE 3.44

The parts of the endocardial heart tube within

the pericardium.

aortic sac

atrium

sinus venosus

ventricle

aortic sac

bulbus cordis

horns of sinus

venosus

atrium

aortic sac

truncus

arteriosus

lower part of

bulbus cordis

atrium

sinus venosus

ventricle

aortic sac

aortic

sac

bulbus cordis

truncus arteriosus

ventricle

right atrium

left atrium

right ventricle

ventricular septum

left ventricle

atrioventricular canal

FIGURE 3.45

The bending of the heart tube within the pericardial cavity. The interior of the developing ventricles is shown at

Figs. 3.15, 3.36, and 3.48).

immediately enters the lowest part of the right atrium (see

phragm opposite the eighth thoracic vertebra and almost

The inferior vena cava pierces the central tendon of the dia

Inferior Vena Cava

at the level of the seventh thoracic vertebra (see Fig. 2.11).

fourth to the eighth intercostal veins. It joins the azygos vein

The superior hemiazygos vein is formed by the union of the

Superior Hemiazygos Vein

tinal veins.

medias

lower left intercostal veins

tributaries some

right and joins the azygos vein (see Fig. 2.11). It receives as

about the level of the eighth thoracic vertebra, turns to the

It ascends through the left crus of the diaphragm and, at

of the left ascending lumbar vein and the left subcostal vein.

The inferior hemiazygos vein is often formed by the union

Inferior Hemiazygos Vein

mediastinal veins.

and numerous

veins,

inferior hemiazygos

superior

intercostal vein,

right superior

eight lower right intercostal veins,

The azygos vein has numerous tributaries, including

cava (Fig. 3.15).

to empty into the posterior surface of the superior vena

Here it arches forward above the root of the right lung

aorta to the level of the fifth thoracic vertebra (Fig. 3.48).

tic opening in the diaphragm on the right side of the

It ascends through the aor

right subcostal vein.

right ascending lumbar vein

formed by the union of the

The origin of the azygos vein is variable. It is often

Azygos Vein

the diaphragm, the bronchi, and the esophagus (Fig. 3.48).

tal spaces, the posterior abdominal wall, the pericardium,

They drain blood from the posterior parts of the intercos

rior hemiazygos vein, and the superior hemiazygos vein.

The azygos veins consist of the main azygos vein, the infe

Azygos Veins

dium (Figs. 3.15 and 3.48).

of the superior vena cava just before it enters the pericar

the bottom right.

and the

the

and

Basic Anatomy

septum primum

endocardial

cushion

sinuatrial

orifice

foramen
primum

atrioventricular
canal

septum secundum

right atrium

interventricular

foramen

septum
primum

foramen
secundum

septum
intermedium

septum primum
breaking down

left atrium

septum
intermedium

septum secundum

septum primum

foramen ovale

membranous part of

ventricular septum

muscular part of

ventricular septum

septum secundum

septum primum

foramen ovale

crista terminalis

formed from

septum spurium

valve of inferior

vena cava

valve of

coronary sinus

FIGURE 3.46

The division of the primitive atrium into the right and left atria by the appearance of the septa. The sinuatrial

orifice and the fate of the venous valves are shown, as is the appearance of the ventricular septum.

Azygos Veins and Caval Obstruction

In obstruction of the superior or inferior venae cavae, the

azygos veins provide an alternative pathway for the return of

venous blood to the right atrium of the heart. This is possible

because these veins and their tributaries connect the superior

and inferior venae cavae.

C L I N I C A L N O T E S

Pulmonary Veins

ated blood to the left atrium of the heart (Figs. 3.15, 3.35,

Two pulmonary veins leave each lung carrying oxygen-

and 3.39).

arches over the apex of the left lung.

the esophagus to enter the root of the neck (Fig. 3.15). It

3.49). It runs upward along the left side of the trachea and

behind the left common carotid artery (Figs. 3.34, 3.35, and

arises from the aortic arch

left subclavian artery

The

sternoclavicular joint.

the left of the trachea and enters the neck behind the left

phalic artery (Figs. 3.34 and 3.49). It runs upward and to

surface of the aortic arch on the left side of the brachioce

arises from the convex

left common carotid artery

The

right sternoclavicular joint.

subclavian and right common carotid arteries behind the

and to the right of the trachea and divides into the right

of the aortic arch (Figs. 3.34 and 3.49). It passes upward

arises from the convex surface

brachiocephalic artery

The

Branches

descending aorta.

level of the sternal angle, becomes continuous with the

passes downward to the left of the trachea and, at the

of the trachea (its main direction is backward). It then

and arches upward, backward, and to the left in front

aorta (Fig. 3.34). It lies behind the manubrium sterni

The arch of the aorta is a continuation of the ascending

Arch of the Aorta

of these important arteries is described on pages 86 to 87.

terior aortic sinus (Figs. 3.34 and 3.41). The further course

arises from the left pos

left coronary artery

sinus, and the

arises from the anterior aortic

right coronary artery

The

Branches

each aortic valve cusp.

one behind

sinuses of the aorta,

possesses three bulges, the

nary trunk in a sheath of serous pericardium. At its root, it

pericardium (Fig. 3.32) and is enclosed with the pulmo

(Fig. 3.34). The ascending aorta lies within the fibrous

where it becomes continuous with the arch of the aorta

right half of the sternum at the level of the sternal angle,

and runs upward and forward to come to lie behind the

The ascending aorta begins at the base of the left ventricle

Ascending Aorta

descending thoracic aorta, and abdominal aorta.

into the following parts: ascending aorta, arch of the aorta,

sues of the body. It is divided for purposes of description

ated blood from the left ventricle of the heart to the tis

The aorta is the main arterial trunk that delivers oxygen

Large Arteries of the Thorax

Aorta

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-

CHAPTER 3

The Thorax: Part II—The Thoracic Cavity

Upper Part of Bulbus Cordis

Lower Part of Bulbus Cordis

blood in

pulmonary trunk

aorta

pulmonary trunk

right bulbar ridge

septum

intermedium
(endocardial

cushions)

left bulbar

ridge

interventricular

foramen

ventricular septum

(muscular part)

spiral

aorticopulmonary

septum

blood entering

aorta

right

bulbar

ridge

right

atrioventricular

opening

left

bulbar

ridge

septum

intermedium
(endocardial

cushions)

right

ventricle

FIGURE 3.47

The division of the bulbus cordis by the spiral aorticopulmonary septum into the aorta and pulmonary trunk.

) is called the membranous part of the ventricular septum.

) and the septum intermedium (

The area of the ventricular septum that is formed from the

) and the muscular part of the ventricular septum.

), which then grow down and join the septum interme

the formation of the spiral septum by fusion of the bulbar ridges (

The lower part of the bulbus cordis showing

The spiral septum in the truncus arteriosus (upper part of the bulbus cordis).

red

dium (blue

fused bulbar ridges (red

blue

inferior thyroid vein

left internal jugular vein

left subclavian vein

left brachiocephalic vein

left internal thoracic vein

left pulmonary veins

great cardiac vein

inferior vena cava

branches of
anterior cardiac vein

superior vena cava

right
brachiocephalic vein

left internal jugular vein

left subclavian vein

left brachiocephalic vein

posterior intercostal veins

hemiazygos veins

hepatic veins

left suprarenal vein

left testicular (ovarian) vein

inferior vena cava

median sacral vein

right brachiocephalic vein

superior vena cava

azygos vein

inferior phrenic vein

right suprarenal vein

right renal vein

right testicular (ovarian) vein

right lumbar veins

right common iliac vein

right internal iliac vein

right external iliac vein

FIGURE 3.48

Major veins draining into the superior and inferior venae cavae.

Major veins entering the heart.

Basic Anatomy

arch of aorta

brachiocephalic
artery

ascending

aorta

celiac artery

superior

mesenteric artery

testicular

(ovarian) artery

median

sacral artery

left common carotid artery

left subclavian

artery

axillary artery

posterior

intercostal

arteries

descending

thoracic

aorta

inferior

phrenic artery

suprarenal artery

renal artery

abdominal aorta

lumbar artery

inferior

mesenteric artery

common iliac artery

internal iliac artery

external iliac artery

FIGURE 3.49

Major branches of the aorta.

(Fig. 3.32).

fibrous pericardium and a sheath of serous pericardium

Together with the ascending aorta, it is enclosed in the

dividing into right and left pulmonary arteries (Fig. 3.11).

long and terminates in the concavity of the aortic arch by

ward, and to the left (Fig. 3.34). It is about 2 in. (5 cm)

upper part of the right ventricle and runs upward, back

the right ventricle of the heart to the lungs. It leaves the

The pulmonary trunk conveys deoxygenated blood from

Pulmonary Trunk

small branches that are distributed to these organs.

are

bronchial arteries

Pericardial, esophageal,

border of the 12th rib to enter the abdominal wall.

are given off on each side and run along the lower

arteries

Subcostal

nine intercostal spaces on each side (Fig. 3.49).

are given off to the lower

Posterior intercostal arteries

Branches

continuous with the abdominal aorta.

(through the aortic opening) in the midline and becomes

the 12th thoracic vertebra, it passes behind the diaphragm

the vertebral column (Figs. 3.15 and 3.49). At the level of

ing forward and medially to reach the anterior surface of

It runs downward in the posterior mediastinum, inclin

the 4th thoracic vertebra (i.e., opposite the sternal angle).

aorta on the left side of the lower border of the body of

astinum and begins as a continuation of the arch of the

The descending thoracic aorta lies in the posterior medi

Descending Thoracic Aorta

and

CHAPTER 3

necessary.

ventricle (Fig. 3.37). Surgical ligation of the ductus is then

pulmonary hypertension and hypertrophy of the right

blood will enter the pulmonary circulation, producing

birth, the ductus closes. Should it remain patent, aortic

lower border of this structure (Figs. 3.15 and 3.35). After

lungs. The left recurrent laryngeal nerve hooks around the

the pulmonary trunk to the aorta, thus bypassing the

ductus arteriosus, which in the fetus conducts blood from

3.35). The ligamentum arteriosum is the remains of the

lower concave surface of the aortic arch (Figs. 3.15 and

connects the bifurcation of the pulmonary trunk to the

is a fibrous band that

ligamentum arteriosum

The

(Figs. 3.11, 3.15, and 3.34).

of the descending aorta to enter the root of the left lung

runs to the left in front

left pulmonary artery

The

the right lung (Figs. 3.11, 3.15, and 3.34).

ascending aorta and superior vena cava to enter the root of

runs to the right behind the

right pulmonary artery

The

Branches

The Thorax: Part II—The Thoracic Cavity

Patent Ductus Arteriosus

The ductus arteriosus represents the distal portion of the sixth

left aortic arch and connects the left pulmonary artery to the

beginning of the descending aorta (Fig. 3.37D). During fetal

life, blood passes through it from the pulmonary artery to the

aorta, thus bypassing the lungs. After birth, it normally con-

stricts, later closes, and becomes the ligamentum arteriosum.

Failure of the ductus arteriosus to close may occur as an

isolated congenital abnormality or may be associated with

congenital heart disease. A persistent patent ductus arte-

riosus results in high-pressure aortic blood passing into the

pulmonary artery, which raises the pressure in the pulmonary

circulation. A patent ductus arteriosus is life threatening and

should be ligated and divided surgically.

C L I N I C A L N O T E S

Aneurysm and Coarctation of the Aorta

the lower borders of the ribs, producing characteristic notch

terior intercostal arteries. The dilated intercostal arteries erode

To compensate for the diminished volume of blood reaching the

lumen becomes narrowed. Later, when fibrosis takes place, the

from an unusual quantity of ductus arteriosus muscle tissue in

of the ligamentum arteriosum. This condition is believed to result

The arch of the aorta lies behind the manubrium sterni. A gross

dilatation of the aorta (aneurysm) may show itself as a pulsatile

swelling in the suprasternal notch.

Coarctation of the aorta is a congenital narrowing of the

aorta just proximal, opposite, or distal to the site of attachment

the wall of the aorta. When the ductus arteriosus contracts, the

ductal muscle in the aortic wall also contracts, and the aortic

aortic wall also is involved, and permanent narrowing occurs.

Clinically, the cardinal sign of aortic coarctation is absent

or diminished pulses in the femoral arteries of both lower limbs.

lower part of the body, an enormous collateral circulation devel-

ops, with dilatation of the internal thoracic, subclavian, and pos-

ing, which is seen on radiographic examination. The condition

should be treated surgically.

C L I N I C A L N O T E S

Lymph Nodes and Vessels of the

the left edge of the esophagus to enter the root of the neck

racic vertebra (sternal angle). It then runs upward along

the level of the lower border of the body of the 4th tho

and reaches the left border of the esophagus (Fig. 3.6B) at

It gradually crosses the median plane behind the esophagus

in the diaphragm, on the right side of the descending aorta.

It ascends through the aortic opening

cisterna chyli.

sac, the

The thoracic duct begins below in the abdomen as a dilated

chea and superior vena cava.

tant neighboring mediastinal structures, such as the tra

enlargement of these nodes may exert pressure on impor

bronchomediastinal trunks and thoracic duct. Disease and

lymph from mediastinal structures and empty into the

are found scattered through the mediastinum. They drain

In addition to the nodes draining the lungs, other nodes

lymph enters the thoracic duct.

lying near the heads of the ribs. From here, the

costal nodes

posterior inter

intercostal spaces drain backward to the

side. The deep lymph vessels of the posterior parts of the

left side and the bronchomediastinal trunk on the right

From here, the lymph passes to the thoracic duct on the

along the internal thoracic blood vessels.

thoracic nodes

internal

parts of the intercostal spaces drain forward to the

The deep lymph vessels of the anterior

rior axillary nodes.

poste

the skin of the posterior thoracic wall drain to the

The lymph vessels of

anterior axillary nodes.

drain to the

The lymph vessels of the skin of the anterior thoracic wall

Thoracic Wall

Thorax

Mediastinum

-
-

Thoracic Duct

(Fig. 3.6B). Here, it bends laterally behind the carotid sheath

artery to enter the beginning of the left brachiocephalic vein.

front of the left phrenic nerve and crosses the subclavian

and in front of the vertebral vessels. It turns downward in