SURFACE MARKING
The bony and soft tissue surface landmarks have been
described in Chapter 12.
The surface marking of important structures is
described here.
o Pleura (Fig.21.1)
o Lungs (Figs 2L.2 to 21.4)
e Heart (Fig.21.5)
. Cardiac valves (Fi9.21,$)
Surfoce Morking of Poilelol Pleuro
The ceraical pleura is represented by a curved line
forming a dome over the medial one-third of the clavicle
with a height of about 2.5 cm above the clavicle
(Fig. 21.1). Pleura lies in the root of neck on both sides.
The anterior margin, the costomediastinal line of
pleural reflection is as follows: On the dght side, it
extends from the sternoclavicular joint downwards and
medially to the midpoint of the sternal angle. From here
it continues vertically downwards to the midpoint of
the xiphisternal joint crosses to right of xiphicostal
angle. On the left side, the line follows the same course
up to the level of the fourth costal cartilage. It then
arches outwards and descends along the stemal margin
up to the sixth costal cartilage.
The inferior margin, or the costodiaphragmatic line
of pleural reflection passes laterally from the lower limit
of its anterior margin, so that it crosses the eighth rib in
the midclavicular line, the tenth rib in the midaxillary
line, and the twelfth rib at the lateral border of the
sacrospinalis muscle (Frg. 21.2). Further it passes
horizontally a little below the 12th rib to the lower
border of the twelfth thoracic vertebra, 2 cm lateral to
the upper border of the twelfth thoracic spine (Fig. 21.3).
Thus the pleurae descend below the costal margin
at three places, at the right xiphicostal angle, and at
the right and left costovertebral angles below the
twelfth rib behind the upper poles of the kidneys. The
latter fact is of surgical importance in exposure of
the kidney. The pleura may be damaged at these sites
(Fig. 21.1).
The posterior margins of the pleura pass from a point
2 cm lateral to the twelfth thoracic spine to a point 2 cm
lateral to the seventh cervical spine. The costal pleura
becomes the mediastinal pleura along this line
(Fig.21.3).
Suiloce Morking of the lung/Visce]ol Pleuro
The apex of the lung coincides with the cervical pleura,
and is represented by a line convex upwards rising
2.5 cm above the medial one-third of the clavicle
(Fis.21..a).
The anterior border of the right lung cotesponds very
closely to the anterior margin or costomediastinal line
of the pleura and is obtained by joining:
. A point at the sternoclavicular joint,
. A point in the median plane at the sternal angle,
. A point in the median plane just above the
xiphisternal joint.
The anterior border of the left lung corresponds to the
anterior margin of the pleura up to the level of the
fourth costal cartilage.
In the lower part, 7t presents a cardiac notch of
variable size. From the level of the fourth costal cartilage
it passes laterally for 3.5 cm from the sternal margin,
and then curves downwards and medially to reach the
sixth costal cartilage 4 cm from the median plane. In
the region of the cardiac notch, the pericardium is
covered only by a double layer of pleura. The area of
the cardiac notch is dull on percussion and is called the
area of superficial cardiac dullness.
Tlte louter border of each lung lies two ribs higher than
the parietal pleural reflection. It crosses the sixth rib in
the midclavicular line, the eighth rib in the midaxillary
line, the tenth rib at the lateral border of the erector
spinae, and ends 2 cm lateral to the tenth thoracic spine.
The posterior border coincides with the posterior
margin of the pleural reflection except that its lower
end lies at the level of the tenth thoracic spine.
The oblique fissure can be drawn by joining:
1 A point 2 cm lateral to the third thoracic spine.
2 Another point on the fifth rib in the midaxillary
line (Figs 21.2 and27.3).
3 A third point on the sixth costal cartilage 7.5 cm
from the median plane.
The horizontal fissure is represented by a line joining:
L A point on the anterior border of the right lung at
the level of the fourth costal cartilage.
2 A second point on the fifth rib in the midaxillary
line (Fig.21.2).
Between the visceral and parietal pleurae the recesses
are present. Costodiaphragmatic are present on both
sides and are about 4-5 cm deep. Costomediastinal is
prominent on left side, to left of sternum between 4th
and 6th costal cartilages.
Suffoce Morking of ihe Borders of the Heort
The upper border is marked by a straight line joining:
1 A point at the lower border of the second left costal
cartilage about 1.3 cm from the sternal margin.
2 A point at the upper border of the third right costal
cartilage 0.8 cm from the sternal margin (Fi9.21.5).
The lower border is marked by a straight line joining:
L A point at the lower border of the sixth right costal
cartilage 2 cm from the sternal margin.
2 A point at the apex of the heart in the left fifth
intercostal space 9 cm from the midsternal line.
The right border is marked by a line, slightly convex
to the right, joining the right ends of the upper and
lowerborders. The maximum convexity is about 3.8 cm
from the median plane in the fourth space.
The left border is marked by a line, fairly convex to
the left, joining the left ends of the upper and lower
borders.
Atrioventricular groove is marked by a line drawn
from the sternal end of left 3rd costal cartilage to the
sternal end of right sixth costal cartilage.
The area of the chest wall overlying the heart is called
the precordium.
Surfoce Morking of the Cordioc lves ond
the Auscultotory Areos
Sound produced by closure of the valves of the heart
can be heard using a stethoscope. The sound arising in
relation to a particular valve are best heard not directly
over the valve, but at areas sifuated some distance away
from the valve in the direction of blood flow through
it. These are called auscultatory areas. The position
of the valves in relation to the surface of the body, and
of the auscultatory areas is given in Table 27.7 and
Fig.2r.6.
Aileries
Infen ol Mamrnary ffihorscre) A ry
It is marked by joining the following points (Fi9.27.7).
L A point 1 cm above the sternal end of the clavicle,
3.5 cm from the median plane.
2 Points marked over the upper 6 costal cartilages at a
distance of 1,.25 cm from the lateral stemal border.
3 The last point is marked in the sixth space 1.25 cm
from the lateral sternal border.
P or)#ry fflur?k
1 First mark the pulmonary valve by a horizontal line
2.5 cm long, mainly along the upper border of the
left 3rd costal cartilage and partly over the adjoining
part of the stemum (Fi9.21,.6).
2 Then mark the pulmonary trunkby two parallel lines
2.5 cm apart from the pulmonary orifice upwards to
the left 2nd costal cartilage.
1 First mark the aortic orifice by a slightly oblique line
2.5 cm long running downwards and to the right
over the left half of the sternum beginning at the level
of the lower border of the left 3rd costal cartilage
(Fig. 21.6).
2 Then mark the ascending aorta by two parallel lines
2.5 cm apart from the aortic orifice upwards to the
right half of the sternal angle (Fig. 21.6).
Areh of the Aorta
Arch of the aorta lies behind the lower half of the
manubrium sterni. Its upper convex border is marked
by a line which begins at the right end of the sternal
angle, arches upwards and to the left through the centre
of the manubrium, and ends at the sternal end of the
left second costal cartilage. Note that the beginning and
the end of the arch lie at the same level. When marked
on the surface as described above, the arch looks much
smaller than it actually is because of foreshortening
(Fig.21.8).
Descending thoracic aorta is marked by two parallel
lines 2.5 cm apart, which begin at the stemal end of the
left second costal cartilage, pass downwards and
medially, and end in the median plane 2.5 cm
the transpyloric plane (Fig. 21.8).
Eraahiac Artery
Brachiocephalic artery is markedby a broad line
extending from the centre of the manubrium to the right
sternoclavicular joint (Fig. 21.8).
The thoracic part of this artery is marked by a broad
line extending from a point a little to the left of the centre
of the manubrium to the left sternoclavicular joint.
Lett Subelavian Artery
The thoracic part of the left subclavian artery is marked
by a broad vertical line along the left border of the
manubrium a little to the left of the left common carotid
artery.
Veins
Srperdor nfl Csys
Superior vena cava is marked by two parallel lines 2 cm
apart, drawn from the lower border of the right first
costal cartilage to the upper border of the third right
costal cartilage, overlapping the right margin of the
sternum (Fig.21.9).
It is marked by two parallel lines 1.5 cm apart, drawn
from the medial end of the right clavicle to the lower
border of the right first costal cartilage close to the
sternum (Fi9.21.9).
LeflBrsahioeephslic in
It is marked by two parallel lines 1.5 cm apart, drawn
from the medial end of the left clavicle to the lower
border of the first right costal cartilage. It crosses the
left sternoclavicular joint and the upper half of the
manubrium (Fig.27.9).
Trachea is marked by two parallel lines 2 cm apart,
drawn from the lower border of the cricoid cartilage (2
cm below the thyroid notch) to the sternal angle,
inclining slightly to the right (Fig. 21J.0).
t Branchu,s
Right bronchus is marked by a broad line running
downwards and to the right for 2.5 cm from the lower
end of the trachea to the stemal end of the right third
costal cartilage.
Left Bronchus
Left bronchus is marked by a broad line running
downwards and to the left for 5 cm from the lower end
of the trachea to the left third costal cartilage 4 cm from
the median plane (Fig. 21.10).
It is marked by two parallel lines 2.5 cm apart by joining
the following points:
1 Two points 2.5 cm apart at the lower border of the
cricoid cartilage across the median plane (Fig. 21.71).
2 Two points 2.5 cm apart at the root of the neck a little
to the left of the median plane.
3 Two points 2.5 cm apart at the sternal angle across
the median plane.
4 Two points 2.5 cm apart at the left 7th costal cartilage
2.5 cm from the median plane.
Thorcci* Duet
It is marked by joining the following points.
1 A point 2 cm above the transpyloric plane slightly
to the right of the median plane (Fig.21.10).
2 A second point 2 cm to right of median plane below
manubriosternal ang1e.
A third point across to left side at same level.
A fourth point 2.5 cm above the left clavicle
2 cm from the median plane.
5 A fifth point just above the sternal angle 1.3 cm to
the left of the median plane.
RADIOGRAPHY
The most commonly taken radiographs are described
as posteroanterior (PA) views. X-rays travel from
posterior to the anterior side. A study of such radio-
graphs gives information about the lungs, the dia-
phragm, themediastinum, the trachea, andthe skeleton
of the region (Fig. 27.12) . Take radiograph keeping both
hands on waist to clear lung fields from scapula.
Following structureshave tobe examined in postero-
anterior view of the thorax.
Sotl Tissues
Nipples in both the sexes may be seen over the lung
fields. The female breasts will also be visualised over
the lower part of the lung fields. The extent of the
overlap varies according to the size and pendulance of
the breasts.
Bones
The bones of the vertebrae are partially visible. Costo-
transverse joints are seen on each side. The posterior
parts of the ribs are better seen because of the large
amounts of calcium contained in them. The ribs get
wider and thinner as they pass anteriorly. Costal
cartilages are not seen unless these are calcified. The
medial borders of the scapulae may overlap the
periphery of the lung fields.
Tlocheo
Trachea is seen as air-filled shadow in the midline of
the neck. It lies opposite the lower cervical and upper
thoracic vertebrae (Fig. 21.12).
Diophrogm
Diaphragm casts dome-shaped shadows on the two
sides. The shadow on the right side is little higher than
on the left side. The angles where diaphragm meets
the thoracic cage are the costophrenic angles-the right
and the left. Under the left costophrenic angle is mostly
the gas in the stomach, while under the right angle is
the smooth shadow of the liver.
Lungs
The dense shadows are cast by the lung roots due to
the presence of the large bronchi, pulmonary vessels,
bronchial vessels and lymph nodes. The lungs readily
permit the passage of the X-rays and are seen as
translucent shadows during full inspiration. Bothblood
vessels and bronchi are seen as series of shadows
radiating from the lung roots. The smaller bronchi are
not seen. The lung is divided into three zones-upper
zone is from the apex till the second costal cartilage.
Middle zone extends from the second to the fourth
costal cartilage. It includes the hilar region. Lower zone
extends from the fourth costal cartilage till the bases of
the lungs.
Medioslinum
Shadow is produced by the superimpositions of
structures in the mediastinum. It is chiefly produced
by the heart and the vessels entering or leaving the
heart. The transverse diameter of heart is half the
transverse diameter of the thoracic cage. During
inspiration, heart descends down and acquires fubular
shape. Right border of the mediastinal shadow is
formed from above downwards by right brachio-
cephalic vein, superior vena cava, right atrium and
inferior vena cava. The left border of mediastinal
shadow is formed from above downwards by aortic
arch (aortic knuckle), left margin of pulmonary trunk,
left auricle and left ventricle. The inferior border of the
mediastinal shadow blends with the liver and
diaphragm.
TOMOGRAPHY
Tomography is a radiological technique by which
radiograms of selected layers (depths) of the body can
be made. Tomography is helpful in locating deeply
situated small lesions which are not seen in the usual
radiograms
NOMERICALS
Anteroposterior diameter of inlet of thorax-S cm.
Transverse diameter of inlet of thorax-1O cm.
Suprasternal notch-T2 vertebra.
Sternal angle-disc between T4 and T5 vertebra. 2nd
costal cartilage articulates with the sternum.
Xiphisternal joint-T9 vertebra.
Subcostal angle-between sternal attachments of 7th
costal cartilages.
Vertebra prominence -7 th cervical spine.
Superior angle of scapula-level of T2 spine.
Root of spine of scapula-level of T3 spine.
Inferior angle of scapula-level of T7 spine.
Length of oesophagus-2S cm:
– Cervical part-4 cm.
– Thoracic part-20 cm.
– Abdominal part-1.25 cm.
– Beginning of oesophagus-C6 vertebra.
– Termination of oesophagus-T11 vertebra.
Beginning of trachea-C6 vertebra:
– Length of trachea-10-15 cm.
– Bifurcation of trachea-upper border of T5
vertebra.
– Length of right principal bronchus-2.S cm.
– Length of left principal bronchus-S cm.
