Lymph nodes and vessels and nerves of the thorax pdf - Thorax

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

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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

Basic Anatomy

the pericardium and mediastinal parietal pleura.

central region of the upper surface of the diaphragm, and

the undersurface of the diaphragm, the pleura covering the

system from the peritoneum covering the central region of

The afferent fibers carry sensation to the central nervous

of the diaphragm.

to the muscle

sole nerve supply

The efferent fibers are the

The phrenic nerves possess efferent and afferent fibers.

its underaspect.

muscle and supply the central part of the peritoneum on

reaching the diaphragm, the terminal branches pierce the

dium, which separates the nerve from the left ventricle. On

lung and then descends over the left surface of the pericar

of the root of the left

in front

the left vagus nerve. It passes

of the aortic arch (Fig. 3.15) and here crosses the left side of

left side of the left subclavian artery. It crosses the left side

descends in the thorax along the

left phrenic nerve

The

its underaspect.

phragm to supply the central part of the peritoneum on

branches pass through the caval opening in the dia

the inferior vena cava to the diaphragm. Its terminal

the right atrium. It then descends on the right side of

side of the pericardium, which separates the nerve from

of the root of the right lung and runs along the right

in front

superior vena cava (Figs. 3.6 and 3.15). It passes

the right side of the right brachiocephalic vein and the

descends in the thorax along

right phrenic nerve

The

rami of the 3rd, 4th, and 5th cervical nerves (see page

The phrenic nerves arise from the neck from the anterior

external laryngeal branch of the vagus).

roid muscle, a tensor of the cord, which is supplied by the

muscles acting on the left vocal cord (except the cricothy

the esophagus on the left side (Fig. 3.6). It supplies all the

sum and ascends in the groove between the trachea and

3.15 and 3.35). It hooks around the ligamentum arterio

vagus trunk as the nerve crosses the arch of the aorta (Figs.

arises from the left

left recurrent laryngeal nerve

The

the trachea and esophagus.)

hooks around the subclavian artery and ascends between

laryngeal nerve arises from the right vagus in the neck and

to the left recurrent laryngeal nerve. (The right recurrent

gives off cardiac branches, and the left vagus gives origin

Both vagi supply the lungs and esophagus. The right vagus

Branches

reach the anterior surface of the stomach.

opening in the diaphragm in front of the esophagus to

It then passes through the esophageal

esophageal plexus.

of the esophagus and takes part in the formation of the

ing the plexus, the vagus passes onto the anterior surface

On leav

pulmonary plexus.

assists in the formation of the

the root of the left lung and

behind

then turns backward

and is itself crossed by the left phrenic nerve. The vagus

3.6 and 3.15). It then crosses the left side of the aortic arch

left common carotid and the left subclavian arteries (Figs.

descends in the thorax between the

left vagus nerve

The

reach the posterior surface of the stomach.

geal opening of the diaphragm behind the esophagus to

It then passes through the esopha

esophageal plexus.

surface of the esophagus and takes part in the formation of

On leaving the plexus, the vagus passes onto the posterior

pulmonary plexus.

lung and assists in the formation of the

the root of the right

behind

azygos vein (Fig. 3.15). It passes

lateral to the trachea and medial to the terminal part of the

posterolateral to the brachiocephalic artery (Fig. 3.6), then

descends in the thorax, first lying

right vagus nerve

The

Vagus Nerves

veins at the root of the neck.

Alternatively, the trunks open independently into the great

opens into the beginning of the right brachiocephalic vein.

common duct, if present, is about 0.5 in. (1.3 cm) long and

tively, may join to form the right lymphatic duct. This

right upper limb, and the right side of the thorax, respec

trunks, which drain the right side of the head and neck, the

The right jugular, subclavian, and bronchomediastinal

Right Lymphatic Duct

arm (see Fig 1.21).

side of the thorax, and left side of the head, neck, and left

from the lower limbs, pelvic cavity, abdominal cavity, left

The thoracic duct thus conveys to the blood all lymph

large veins.

although they may drain directly into the adjacent

trunks,

bronchomediastinal lymph

left jugular, subclavian,

At the root of the neck, the thoracic duct receives the

and

Nerves of the Thorax

the

Phrenic Nerves

618).

paralysis of the diaphragm on one side, was once used as part

Paralysis of the Diaphragm

The phrenic nerve may be paralyzed because of pressure

from malignant tumors in the mediastinum. Surgical crush-

ing or sectioning of the phrenic nerve in the neck, producing

of the treatment of lung tuberculosis, especially of the lower

lobes. The immobile dome of the diaphragm rests the lung.

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

Thoracic Part of the Sympathetic Trunk

stellate ganglion.

ganglion to form the

The first ganglion is often fused with the inferior cervical

passing to the corresponding spinal nerve.

communicans

gray ramus

white

tally arranged ganglia, each with

The sympathetic trunk has 12 (often only 11) segmen

medial arcuate ligament.

body of the 12th thoracic vertebra by passing behind the

of the ribs (Fig. 3.15). It leaves the thorax on the side of the

ture in the mediastinum and runs downward on the heads

the sympathetic trunk. It is the most laterally placed struc

above with the cervical and below with the lumbar parts of

The thoracic part of the sympathetic trunk is continuous

and

100

CHAPTER 3

Branches

The Thorax: Part II—The Thoracic Cavity

Gray rami communicantes go to all the thoracic spinal

sweat glands, and arrector pili muscles of the skin.

the branches of the spinal nerves to the blood vessels,

nerves. The postganglionic fibers are distributed through

The first five ganglia give postganglionic fibers to the

heart, aorta, lungs, and esophagus.

The lower eight ganglia mainly give preganglionic fib

of these nerves in the abdomen, see page 224.

arises from ganglion 12. For details of the distribution

lowest splanchnic nerve

ganglia 10 and 11, and the

arises from

lesser splanchnic nerve

ganglia 5 to 9, the

arises from

greater splanchnic nerve

diaphragm. The

They enter the abdomen by piercing the crura of the

nerves (Fig. 3.15) and supply the abdominal viscera.

ers, which are grouped together to form the splanchnic

pathectomy causes vasodilatation of the arterioles in the

ganglia can be performed to increase the blood flow to the

Preganglionic sympathectomy of the 2nd and 3rd thoracic

Sympathetic Trunk in the Treatment of Raynaud

Disease

fingers for such conditions as Raynaud disease. The sym-

upper

A high spinal anesthetic may block the preganglionic sympa

limb.

Spinal Anesthesia and the Sympathetic Nervous

System

thetic fibers passing out from the lower thoracic segments of

the spinal cord. This produces temporary vasodilatation below

this level, with a consequent fall in blood pressure.

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

Esophagus

and internal thoracic arteries.

The blood supply of the thymus is from the inferior thyroid

site for development of T (thymic) lymphocytes.

involution. It has a pink, lobulated appearance and is the

continues to grow until puberty but thereafter undergoes

of the great vessels into the root of the neck. The thymus

may extend up through the superior mediastinum in front

largest size relative to the size of the body, at which time it

anterior mediastinum. In the newborn infant, it reaches its

lying between the sternum and the pericardium in the

The thymus is a flattened, bilobed structure (see Fig. 3.6)

esophagus is surrounded by the esophageal nerve plexus.

thetic trunks. In the lower part of its thoracic course, the

thetic efferent and afferent fibers via the vagi and sympa

The esophagus is supplied by parasympathetic and sympa

and the celiac nodes (see Fig. 3.26).

lower third into nodes along the left gastric blood vessels

the superior and posterior mediastinal nodes, and from the

into the deep cervical nodes, from the middle third into

Lymph vessels from the upper third of the esophagus drain

Lymph Drainage of the Esophagus

gastric vein, a tributary of the portal vein.

into the azygos veins, and from the lower third into the left

drain into the inferior thyroid veins, from the middle third

from the left gastric artery. The veins from the upper third

descending thoracic aorta, and the lower third by branches

rior thyroid artery, the middle third by branches from the

The upper third of the esophagus is supplied by the infe

diaphragm posteriorly.

the left lobe of the liver anteriorly and to the left crus of the

0.5 in. (1.3 cm) and then enters the stomach. It is related to

In the abdomen, the esophagus descends for about

form of a sling.

crus of the diaphragm pass around the esophagus in the

blood vessels, and lymphatic vessels. Fibers from the right

accompanied by the two vagi, branches of the left gastric

terior. At the opening in the diaphragm, the esophagus is

lies anterior to the esophagus, and the right vagus lies pos

The left vagus

esophageal plexus.

thetic nerves to form the

nerves leave the pulmonary plexus and join with sympa

Inferiorly to the level of the roots of the lungs, the vagus

thoracic duct, and the mediastinal pleura (Fig. 3.15)

The left subclavian artery, the aortic arch, the

Left side:

of the azygos vein (see Fig. 3.15)

The mediastinal pleura and the terminal part

Right side:

aorta (Figs. 3.6 and 3.39)

arteries; and, at its lower end, the descending thoracic

racic duct; the azygos veins; the right posterior intercostal

The bodies of the thoracic vertebrae; the tho

Posteriorly:

from the left atrium (Figs. 3.6 and 3.39)

it; and the pericardium, which separates the esophagus

geal nerve; the left principal bronchus, which constricts

The trachea and the left recurrent laryn

Anteriorly:

above downward are as follows:

The relations of the thoracic part of the esophagus from

gus over to the midline (Fig. 3.6).

level of the sternal angle, the aortic arch pushes the esopha

the superior and then the posterior mediastinum. At the

In the thorax, it passes downward and to the left through

the recurrent laryngeal nerves (see page 639).

gland; and anteriorly, it is in contact with the trachea and

column; laterally, it is related to the lobes of the thyroid

In the neck, the esophagus lies in front of the vertebral

tebra to join the stomach (Fig. 3.9).

through the diaphragm at the level of the 10th thoracic ver

the pharynx opposite the sixth cervical vertebra. It passes

long that is continuous above with the laryngeal part of

The esophagus is a tubular structure about 10 in. (25 cm)

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Blood Supply of the Esophagus

Nerve Supply of the Esophagus

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Thymus

Blood Supply