Thoracic wall surface anatomy pdf - Thorax

process of the sternum and the body of the sternum

is the joint between the xiphoid

xiphisternal joint

The

these cases, it may be easier to count up from the 12th rib.

tal spaces are often obscured by large pectoral muscles. In

Occasionally in a very muscular male, the ribs and intercos

then the 2nd rib. All ribs may be counted from this point.

to the left will pass directly onto the 2nd costal cartilage and

seen as a transverse ridge. The finger moved to the right or

position of the sternal angle can easily be felt and is often

between the 4th and 5th thoracic vertebrae (see Fig. 2.2). The

Figs. 2.19 and 2.20). It lies opposite the intervertebral disc

between the manubrium and the body of the sternum (see

is the angle made

sternal angle (angle of Louis)

The

The Thorax: Part I—The Thoracic Wall

(Fig. 2.21). It lies opposite the body of the ninth thoracic

cess of the scapula.

It articulates at its lateral extremity with the acromion pro

length and can be easily palpated (see Figs. 2.19 and 2.20).

is subcutaneous throughout its entire

clavicle

The

lumbar vertebra.

is formed by the 10th rib and lies at the level of the third

Figs. 2.19 and 2.20). The lowest part of the costal margin

10th ribs and the ends of the 11th and 12th cartilages (see

and is formed by the cartilages of the 7th, 8th, 9th, and

is the lower boundary of the thorax

costal margin

The

cartilages (see Fig. 2.21).

sternum, between the sternal attachments of the 7th costal

is situated at the inferior end of the

subcostal angle

The

vertebra (see Fig. 2.2).

■

as the result of calcification and even ossification of the

■

Anatomic and Physiologic Changes in the Thorax

with Aging

Certain anatomic and physiologic changes take place in the

thorax with advancing years:

The rib cage becomes more rigid and loses its elasticity

costal cartilages; this also alters their usual radiographic

appearance.

The stooped posture (kyphosis), so often seen in the

old because of degeneration of the intervertebral discs,

decreases the chest capacity.
Disuse atrophy of the thoracic and abdominal muscles can

result in poor respiratory movements.
Degeneration of the elastic tissue in the lungs and bronchi

results in impairment of the movement of expiration.

These changes, when severe, diminish the efficiency of respi-

ratory movements and impair the ability of the individual to

withstand respiratory disease.

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

Ribs

pressing the fingers upward into the axilla and drawing

The lateral surfaces of the remaining ribs can be felt by

The 1st rib lies deep to the clavicle and cannot be palpated.

them downward over the lateral surface of the chest wall.

esophagus

diaphragm

stomach

peritoneum

FIGURE 2.17

Paraesopha

A. Sliding esophageal hernia. B.

geal hernia.

natomy

aphic

adiog

This is fully described on page 102.

the internal thoracic artery, and posteriorly to the posterior

posterior chest wall passes to the posterior axillary nodes

of the skin of the anterior chest wall

lymph drainage

ing one of the internal thoracic arteries and joining its distal

the myocardium can be revascularized by surgically mobiliz

inserting a graft. The graft most commonly used is the great

sclerosis, the diseased arterial segment can be bypassed by

Internal Thoracic Artery in the Treatment

of Coronary Artery Disease

In patients with occlusive coronary disease caused by athero-

saphenous vein of the leg (see page 453). In some patients,

cut end to a coronary artery.

Lymph Drainage of the Thoracic Wall

The

passes to the anterior axillary lymph nodes; that from the

(Fig. 2.18). The lymph drainage of the intercostal spaces

passes forward to the internal thoracic nodes, situated along

intercostal nodes and the para-aortic nodes in the poste-

rior mediastinum. The lymphatic drainage of the breast is

described on page 337.

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

natomy

face

Anterior Chest Wall

2nd thoracic vertebra (see Fig. 2.2).

2.20). It lies opposite the lower border of the body of the

medial ends of the clavicles in the midline (Figs. 2.19 and

manubrium sterni and is easily felt between the prominent

is the superior margin of the

suprasternal notch

The

Surface Anatomy

trapezius

tendon of

sternocleidomastoid

suprasternal notch

manubrium sterni

body of sternum

anterior axillary fold

xiphoid process

costal margin

linea semilunaris

cubital fossa

site of apex

beat of heart

areola

nipple

pectoralis major

deltoid

sternal angle

(angle of Louis)

acromion process

clavicle

supraclavicular

fossa

FIGURE 2.19

Anterior view of the thorax of a 27-year-old man.

axillary

nodes

watershed

superficial

inguinal

lymph
nodes

posterior

axillary

lymph
nodes

FIGURE 2.18

Lymph drainage of the skin of the thorax and

below as the intercostal spaces are palpated.

ing fingers should gently raise the left breast from

In a female with pendulous breasts, the examin

have the patient lean forward in the sitting position.

Should you have difficulty in finding the apex beat,

left intercostal space 3.5 in. (9 cm) from the midline.

is found. The apex beat is normally found in the fifth

moving them until the point of maximum pulsation

placing two fingers over the intercostal spaces and

determined, the apex beat is accurately localized by

the heart. After the area of cardiac pulsation has been

by placing the flat of the hand on the chest wall over

the heart forward.) The apex beat can usually be felt

the curved aorta to straighten slightly, thus pushing

aorta; the force of the blood in the aorta tends to cause

the ejection of blood from the left ventricle into the

forward with each ventricular contraction because of

racic wall as the heart contracts. (The heart is thrust

apex of the heart being thrust forward against the tho

of the left ventricle. The apex beat is caused by the

The apex of the heart is formed by the lower portion

line. In the female, its position is not constant.

intercostal space about 4 in. (10 cm) from the mid

In the male, the nipple usually lies in the fourth

border of the 5th rib.

line, but the left dome only reaches as far as the lower

as far as the upper border of the 5th rib in the midclavicular

summit of the right dome of the diaphragm arches upward

the xiphisternal joint. In the midrespiratory position, the

The central tendon of the diaphragm lies directly behind

palpating the sternal angle and the second costal cartilage.

an alternative method may be used to identify ribs by first

12th rib is very short and difficult to feel. For this reason,

counting from below. However, in some individuals, the

The 12th rib can be used to identify a particular rib by

lymph flow.

iliac crests posteriorly may be regarded as watersheds for

abdomen. Note that levels of the umbilicus anteriorly and

Diaphragm

Nipple

Apex Beat of the Heart

The Thorax: Part I—The Thoracic Wall

clavicle

acromion

greater tuberosity

of humerus

deltoid

areola

nipple

costal margin

rectus abdominis

umbilicus

iliac crest

xiphoid process

axillary tail of
mammary gland

anterior
axillary fold

pectoralis major

sternal angle
(angle of Louis)

deltopectoral triangle

suprasternal

notch

spine of scapula

posterior fibers

of deltoid

medial border

of scapula

skin furrow over

spinous processes

of lumbar vertebrae

erector spinae

skin dimple
overlying posterior
superior iliac spine

iliac crest

latissimus dorsi

inferior angle
of scapula

trapezius

acromion

FIGURE 2.20

old woman.

Posterior view of the thorax of a 29-year-

Anterior view of the thorax and abdomen of a 29-year-old woman.

Surface Anatomy

vertebra (see Figs. 2.20 and 2.22).

lies on a level with the spine of the seventh thoracic

angle

inferior

thoracic vertebra (see Figs. 2.21 and 2.22). The

root of the spine lies on a level with the spine of the third

is subcutaneous, and the

spine of the scapula

2.22). The

spine of the second thoracic vertebra (see Figs. 2.20 and

lies opposite the

superior angle

surface of the thorax. The

shape and is located on the upper part of the posterior

(shoulder blade) is flat and triangular in

The

below.

vertebra lies posterior to the body of the next vertebra

be noted that the tip of a spinous process of a thoracic

by a large ligament, the ligamentum nuchae. It should

vertebrae. The spines of C1 to 6 vertebrae are covered

Below this level are the overlapping spines of the thoracic

(vertebra prominens).

of the seventh cervical vertebrae

nuchal groove. The first spinous process to be felt is that

posterior surface of the neck and drawn downward in the

finger should be placed on the skin in the midline on the

palpated in the midline posteriorly (Fig. 2.22). The index

can be

thoracic vertebrae

of the

spinous processes

The

Posterior Chest Wall

the lower border of the teres major muscle.

tendon of the latissimus dorsi muscle as it passes around

is formed by the

posterior fold

hard against the hip. The

made to stand out by asking the patient to press a hand

toralis major muscle (see Figs. 2.19 and 2.20). This can be

is formed by the lower border of the pec

anterior fold

The

Axillary Folds

scapula

supraclavicular fossa

clavicle

infraclavicular

fossa

subcostal

angle

costal margin

midsternal line

midclavicular line

anterior axillary line

xiphisternal joint

sternal angle

suprasternal notch

first rib

superior angle

of scapula

inferior angle

of scapula

thoracic

spine seven

12th rib

cervical spine seven

clavicle

acromion

greater tuberosity

of humerus

spine of scapula

medial border

of scapula

lateral border

of scapula

thoracic

spine 12

FIGURE 2.21

Surface landmarks of anterior

thoracic walls.

(A) and posterior

(B)

Clinical Examination of the Chest

ments of respiration, many bony landmarks change their levels

identifiable bony landmarks so that he or she can accurately

detect friction sounds produced by the rubbing together of dis

of the heart can be confirmed by auscultation, and the various

sounds as the air enters and leaves the respiratory passages.

produces a dull note. With practice, it is possible to distinguish

the chest wall is noted. Abnormal pulsations are felt and tender

the chest wall. Abnormal protuberances or recession of part of

As medical personnel, you will be examining the chest to detect

evidence of disease. Your examination consists of inspection,

palpation, percussion, and auscultation.

Inspection shows the configuration of the chest, the range of

respiratory movement, and any inequalities on the two sides. The

type and rate of respiration are also noted.

Palpation enables the physician to confirm the impressions

gained by inspection, especially of the respiratory movements of

areas detected.

Percussion is a sharp tapping of the chest wall with the

fingers. This produces vibrations that extend through the tissues

of the thorax. Air-containing organs such as the lungs produce a

resonant note; conversely, a more solid viscus such as the heart

the lungs from the heart or liver by percussion.

Auscultation enables the physician to listen to the breath

Should the alveoli or bronchi be diseased and filled with fluid, the

nature of the breath sounds will be altered. The rate and rhythm

sounds produced by the heart and its valves during the different

phases of the cardiac cycle can be heard. It may be possible to

eased layers of pleura or pericardium.

To make these examinations, the physician must be familiar

with the normal structure of the thorax and must have a mental

image of the normal position of the lungs and heart in relation to

identifiable surface landmarks. Furthermore, it is essential that

the physician be able to relate any abnormal findings to easily

record and communicate them to colleagues.

Since the thoracic wall actively participates in the move-

with each phase of respiration. In practice, to simplify matters,

the levels given are those usually found at about midway

between full inspiration and full expiration.

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

the inferior angle of the scapula (arms at the sides)

rior wall of the thorax (see Fig. 2.22), passing through

Runs vertically downward on the poste

Scapular line:

rior axillary folds

point situated midway between the anterior and poste

Runs vertically downward from a

Midaxillary line:

the posterior axillary fold

Runs vertically downward from

Posterior axillary line:

the anterior axillary fold (see Fig. 2.21)

Runs vertically downward from

Anterior axillary line:

midpoint of the clavicle (see Fig. 2.21)

Runs vertically downward from the

Midclavicular line:

num (see Fig. 2.21)

Lies in the median plane over the ster

Midsternal line:

face locations on the anterior and posterior chest walls.

Several imaginary lines are sometimes used to describe sur

The Thorax: Part I—The Thoracic Wall

Lines of Orientation

■

be counted from this point. The 12th rib can usually be felt from

second costal cartilage and then the 2nd rib. All other ribs can

When one is examining the chest from in front, the

Rib and Costal Cartilage Identification

sternal

angle is an important landmark. Its position can easily be felt

and often be seen by the presence of a transverse ridge. The

finger moved to the right or to the left passes directly onto the

behind, but in some obese persons this may prove difficult.

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

Trachea

surface by a line drawn from the root of the spine of the

of the lung can be indicated on the

oblique fissure

The

(4 cm) from the midline (Fig. 2.24).

the level of the 10th thoracic vertebra and lies about 1.5 in.

from the spinous process of the 7th cervical vertebra to

extends downward

posterior border of the lung

The

ing inspiration and expiration.

that the level of the inferior border of the lung changes dur

(Figs. 2.23, 2.24, and 2.25). It is important to understand

the 10th rib adjacent to the vertebral column posteriorly

lar line and the 8th rib in the midaxillary line, and reaches

a curving line, which crosses the 6th rib in the midclavicu

in midinspiration follows

lower border of the lung

The

sharply downward to the level of the xiphisternal joint.

placing the lung to the left. The anterior border then turns

(see Fig. 2.23). This notch is produced by the heart dis

cardiac notch

lateral margin of the sternum to form the

ates laterally and extends for a variable distance beyond the

course, but at the level of the fourth costal cartilage it devi

anterior border of the left lung

2.23). The

downward until it reaches the xiphisternal joint (see Fig.

ing the midline behind the sternal angle. It then continues

sternoclavicular joint and runs downward, almost reach

begins behind the

anterior border of the right lung

The

Fig. 2.23).

of the medial and intermediate thirds of the clavicle (see

vicular joint to a point 1 in. (2.5 cm) above the junction

drawing a curved line, convex upward, from the sternocla

mapped out on the anterior surface of the body by

projects into the neck. It can be

apex of the lung

The

palpated in the midline in the suprasternal notch.

left principal bronchi. At the root of the neck, it may be

the right of the midline by dividing into the right and the

(Fig. 2.23). It commences in the midline and ends just to

in the neck to the level of the sternal angle in the thorax

cartilage (opposite the body of the 6th cervical vertebra)

The trachea extends from the lower border of the cricoid

Lungs

has a similar

superior angle

of scapula

spine of

scapula

inferior

angle of

scapula

iliac

crest

nuchal groove

cervical spine seven

thoracic spine one

thoracic spine two

thoracic spine

three

thoracic spine

seven

lateral border

of erector

spinae

muscle

scapular line

FIGURE 2.22

Surface landmarks of the posterior thoracic

wall.

upper lobe

horizontal

fissure

middle

lobe

oblique

fissure

lower

lobe

lower border of pleura

sternal
angle

upper
lobe

cardiac
notch

lower
lobe

FIGURE 2.23

Surface markings of the lungs and parietal

pleura on the anterior thoracic wall.

Surface Anatomy

(see page 62).

diaphragmatic recess

costo

distance between the two borders corresponds to the

same points, the 8th, 10th, and 12th ribs, respectively. The

respectively; the lower margins of the pleura cross, at the

the midaxillary lines, and the sides of the vertebral column,

cross the 6th, 8th, and 10th ribs at the midclavicular lines,

2.24, and 2.25). Note that the lower margins of the lungs

lateral border of the erector spinae muscle (see Figs. 2.23,

12th rib adjacent to the vertebral column—that is, at the

line and the 10th rib in the midaxillary line, and reaches the

curved line, which crosses the 8th rib in the midclavicular

on both sides follows a

lower border of the pleura

The

to the xiphisternal joint (see Fig. 2.23).

cardiac notch of the lung.) It then turns sharply downward

(Note that the pleural cardiac notch is not as large as the

the lateral margin of the sternum to form the cardiac notch.

fourth costal cartilage it deviates laterally and extends to

has a similar course, but at the level of the

of the left pleura

anterior border

until it reaches the xiphisternal joint. The

line behind the sternal angle. It then continues downward

behind the sternoclavicular joint, almost reaching the mid

runs down

anterior border of the right pleura

The

clavicle (see Fig. 2.23).

the junction of the medial and intermediate thirds of the

the sternoclavicular joint to a point 1 in. (2.5 cm) above

lung. A curved line may be drawn, convex upward, from

has a surface marking identical to that of the apex of the

bulges upward into the neck and

cervical pleura

The

lines of pleural reflection.

surface, are referred to as the

limits of the parietal pleura where it lies close to the body

on the surface of the body. The lines, which indicate the

The boundaries of the pleural sac can be marked out as lines

fissure lies the lower lobe.

it lies the middle lobe; below and posterior to the oblique

Above the horizontal fissure lies the upper lobe and below

fissure in the midaxillary line (see Figs. 2.23 and 2.25).

tally along the fourth costal cartilage to meet the oblique

which may be represented by a line drawn horizon

fissure,

horizontal

In the right lung is an additional fissure, the

to it (see Figs. 2.23 and 2.24).

anterior to this line; the lower lobe lies below and posterior

junction. In the left lung, the upper lobe lies above and

lowing the course of the 6th rib to the sixth costochondral

scapula obliquely downward, laterally and anteriorly, fol

Pleura

tomy. The pleura crosses the 12th rib and may be damaged

ratory tract, it should be possible to have a mental image of

of the lungs. When listening to the breath sounds of the respi

the surface markings of the pleural reflections and the lobes

Pleural Reflections

It is hardly necessary to emphasize the importance of knowing

the structures that lie beneath the stethoscope.

The cervical dome of the pleura and the apex of the lungs

extend up into the neck so that at their highest point they lie

about 1 in. (2.5 cm) above the clavicle (see Figs. 2.6, 2.13, and

2.23). Consequently, they are vulnerable to stab wounds in the

root of the neck or to damage by an anesthetist’s needle when

a nerve block of the lower trunk of the brachial plexus is being

performed.

Remember also that the lower limit of the pleural reflection,

as seen from the back, may be damaged during a nephrec-

during removal of the kidney through an incision in the loin.

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

Heart

costal cartilage (remember sternal angle) 0.5 in. (1.3 cm)

great blood vessels, extends from a point on the second left

formed by the roots of the

superior border,

The

3.5 in. (9 cm) from the midline (Fig. 2.26).

the apex beat and is found in the fifth left intercostal space

formed by the left ventricle, corresponds to

apex,

The

both an apex and four borders.

For practical purposes, the heart may be considered to have

upper lobe

oblique

fissure

lower lobe

lower border of pleura

lower lobe

upper lobe

FIGURE 2.24

Surface markings of the lungs and parietal

pleura on the posterior thoracic wall.

cardiac

notch

oblique

fissure

lower border of pleura

oblique
fissure

horizontal

fissure

FIGURE 2.25

Surface markings of the lungs and parietal

pleura on the lateral thoracic walls.

of the sternum (see Fig. 2.26).

the 6th right costal cartilage 0.5 in. (1.3 cm) from the edge

cm) from the edge of the sternum downward to a point on

from a point on the third right costal cartilage 0.5 in. (1.3

formed by the right atrium, extends

right border,

The

num (see Fig. 2.26).

costal cartilage 0.5 in. (1.3 cm) from the edge of the ster

from the edge of the sternum to a point on the third right

The Thorax: Part I—The Thoracic Wall

right

border

superior
border

left
border

apex

inferior

border

FIGURE 2.26

Surface markings of the heart.

Development of the Diaphragm

weak musculature around the esophageal opening in the dia

between the xiphoid and costal origins of the diaphragm, and (c)

peritoneal membranes from the body wall. The herniae occur at

peritoneum from the pleuroperitoneal membranes are derived

nerves. This is understandable, since the peripheral pleura and

lower surfaces of the diaphragm is from the lower six thoracic

peritoneum covering the peripheral areas of the upper and

sensory innervation of the peripheral parts of the pleura and

explains their sensory innervation from the phrenic nerve. The

surface are also formed from the septum transversum, which

surface of the diaphragm and the peritoneum on the lower

phragm is the phrenic nerve. The central pleura on the upper

tery posterior to the esophagus. During the process of fusion,

and 5th cervical segments. With the descent of the heart from

which are largely

pleuroperitoneal membranes,

don; (b) the two

The diaphragm is formed from the following structures: (a) the
septum transversum, which forms the muscle and central ten-

responsible for the peripheral areas of the diaphragmatic pleura

and peritoneum that cover its upper and lower surfaces, respec-

tively; and (c) the dorsal mesentery of the esophagus, in which

the crura develop.

The septum transversum is a mass of mesoderm that is

formed in the neck by the fusion of the myotomes of the 3rd, 4th

the neck to the thorax, the septum is pushed caudally, pulling its

nerve supply with it; thus, its motor nerve supply is derived from

the 3rd, 4th and 5th cervical nerves, which are contained within

the phrenic nerve.

The pleuroperitoneal membranes grow medially from the

body wall on each side until they fuse with the septum trans-

versum anterior to the esophagus and with the dorsal mesen-

the mesoderm of the septum transversum extends into the other

parts, forming all the muscles of the diaphragm.

The motor nerve supply to the entire muscle of the dia-

from the body wall.

Diaphragmatic Herniae
Congenital herniae occur as the result of incomplete fusion of

the septum transversum, the dorsal mesentery, and the pleuro-

the following sites: (a) the pleuroperitoneal canal (more common

on the left side; caused by failure of fusion of the septum trans-

versum with the pleuroperitoneal membrane), (b) the opening

the esophageal hiatus.

Acquired herniae may occur in middle-aged people with

phragm. These herniae may be either sliding or paraesophageal

(Fig. 2.17).

E M B R Y O L O G I C N O T E S

The

the apex beat (see Fig. 2.26).

right costal cartilage 0.5 in. (1.3 cm) from the sternum to

the apical part of the left ventricle, extends from the sixth

formed by the right ventricle and

inferior border,

The

(see Fig. 2.26).

from the edge of the sternum to the apex beat of the heart

from a point on the 2nd left costal cartilage 0.5 in. (1.3 cm)

formed by the left ventricle, extends

left border,

beat may enable a physician to determine whether the heart

Position and Enlargement of the Heart

The surface markings of the heart and the position of the apex

has shifted its position in relation to the chest wall or whether

the heart is enlarged by disease. The apex beat can often be

seen and almost always can be felt. The position of the mar-

gins of the heart can be determined by percussion.

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

Thoracic Blood Vessels

manubrium sterni.

also lie behind the

left brachiocephalic veins

right

and the terminal parts of the

superior vena cava

The

brium sterni (Fig. 2.2).

lie behind the manu

left common carotid arteries

brachiocephalic

and the roots of the

arch of the aorta

The

and

Surface Anatomy

and the overlying skin is wrinkled.

hemispherical shape lost; the breasts then become smaller,

sue of the breast may become reduced in amount and the

dulous. In older women past menopause, the adipose tis

multiparous women, the breasts may be large and pen

the pectoralis major and enters the axilla. In middle-aged

Its upper lateral edge extends around the lower border of

the lateral margin of the sternum to the midaxillary line.

2nd to 6th ribs and their costal cartilages and extends from

spherical shape. In the young adult female, it overlies the

the female after puberty, it enlarges and assumes its hemi

(Fig. 2.20). In the child and in men, it is rudimentary. In

in the superficial fascia covering the anterior chest wall

Chapter 9. To summarize briefly, the mammary gland lies

nodes, it will be fully described with the Upper Limb in

and its main lymph drainage is into the axillary lymph

ture. Because it is closely related to the pectoral muscles

The mammary gland is clinically a very important struc

immediately below their corresponding ribs (see Fig. 2.8).

VAN—is the order from above downward) are situated

The intercostal vessels and nerve (“vein, artery, nerve”—

sixth intercostal space.

the edge of the sternum (see Figs. 2.9 and 2.10), as far as the

posterior to the costal cartilages, 0.5 in. (1.3 cm) lateral to

run vertically downward,

internal thoracic vessels

The

Mammary Gland

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Clinical Cases

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