Parf)
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,sRight 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 BronchusLeft 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.
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.
SURFACE MARKING AND RADIOLOGICAL ANATOMY OF THORAX
Thoracic duct
Fig.
duct
Clavicle
Manubriosternal
angle
Thoracic duct
21 .10: Surface marking of trachea, bronchi and thoracic
Arch of cricoid
Oesophagus
1st costal cartilage
Sternal angle
Left seventh
costal cartilage
Median plane
Fig. 21 .11: Surface marking of the oesophagus
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
3
4