This document provides guidelines for performing and interpreting a normal chest x-ray. It describes recommended projections including PA, AP, lateral, and oblique views. Proper positioning, centering, penetration, and rotation are discussed. Key anatomical structures are defined, such as the mediastinum, heart, lungs, fissures, hila, and diaphragm. Common variations and pathological findings are outlined. The document aims to serve as a reference for radiologists in evaluating and diagnosing chest x-ray images.

1. NORMAL CHEST XRAY
BY
DR.PRABHA JOSEPH

2. CONTENTS
 RECOMMENTED PROJECTIONS
• Position & centering
• Penetration
• Rotation
 MEDIASTINUM
• Junctional lines

3. Lungs
Hidden areas
Diaphragm
Soft tissues
bones

4. RECOMMENDED PROJECTIONS
 BASIC POSTERO-ANTERIOR(ERECT)
 ALTERNATIVE ANTERO-POSTERIOR(ERECT)
ANTERO-POSTERIOR(SUPINE)
ANTERO-POSTERIOR(SEMI ERECT)
 SUPPLEMENTAR LATERAL
POSTERO-ANTERIOR(EXPIRATION)
APICES
LATERAL-UPPER ANTERIOR REGION
DECUBITUS WITH HORIZONTAL BEAM
TOMOGRAPHY

5. POSITIONING:
 A 35 x 45 cm cassette is selected
 Patient positioned facing the cassette, with chin extended
and centered to the middle of the top of the cassette
 Feet paced slightly apart so patient remains steady

6.  Dorsal aspect of hand placed
behind and below the hip with
elbows brought forward or by
allowing the arms to encircle
the cassette therby shoulders
are rotated forward pressed
downward in contact with the
cassete

7. DIRECTION AND CENTERING:
 Horizontal central beam at right angles to the cassette
at the level of 8th thoracic vertebrae(spinous process
of T7)
 Surface marking of T7 is inferior angle of scapula
 Exposure is made in full normal arrested inspiration

8. ESSENTIAL IMAGE CHARECTERISTICS:
• Full lung field with scapula projecting laterally away
from lung field
• Clavicles symmetrical and equidistant from spinous
process and not obscuring the lung apices
• Well inflated(ie anterior six and posterior 10 ribs)

9. Costophrenic angles and
diaphragm outlined clearly
The mediastinum and heart
central and sharply defined
Fine demarcation of the lung
tissues from hilum to periphery

10.  Xray taken in full expiration
to confirm the presence of
pneumothorax(increasing
intrapleural pressure
results in compression of
lung making
pneumothorax bigger)
EXPIRATORY TECHNIQUE

11. ANTERO-POSTERIOR(ERECT)
Patient standing or sitting with
back to cassette, upper edge of
the cassette above lung apices
Median sagittal plane right angle
to the middle of cassette
Shoulders bought downward
and foreward by hands below

12. CENTERING
 Horizontal ray, right angle to
cassette towards sternal
notch
 Exposure taken in full
inspiration

13. ANTEROPOSTERIOR(SUPINE)
 Patient in supine,cassette
placed under patients chest
with upper edge of cassette
above lung apices
 Median sagittal plane –right

14.  Arms rotated laterally and supported by the side
 Head supported on pillow &chin raised
CENTERING:
• Right angled towards sternal notch

15. ANTERO POSTERIOR(SEMI ERECT)
 Patient in semi recumbent
position facing xray tube
 Cassette supported against
the back with upper edge
above apices
 Cassette should be parallel to
coronal plane

16.  Median sagittal plane right angle and to midline of the
cassette
 Arms are rotated medially with shoulders brought forward to
bring scapula clear to lung fields
 CENTERING:
 Towards the sternal notch

17. LATERAL VIEW
 Patient to be turned to bring
side of investigation in contact
with the cassette
 Median sagittal plane is parallel
to the cassette
 Arms are folded over the head
or raised above the head

18.  Mid axillary line coincident
with middle of the film
 Cassette is adjusted to
include apices and lower
lobes to the level of 1st
lumbar vertebrae

19. CENTERING
 Horizontal ray at right angle to the middle of
the cassette at the mid axillary line

20. APICES:
POSITION & CENTERING:
o Patient in PA projection,
central ray angled at 30 degree
caudally towards C7 spinous
process coincident with sternal
angle
o Patient in AP projection ray
angled 30 degree cephalad
towards sternal angle

21. o Patient reclining, and the coronal palne at 30
degree to cassette.nape of neck rests against
upper border of cassette,ray directed towars
sternal angle

22. UPPER ANTERIOR REGION-LATERAL
POSITION & CENTERING:
o Patient positioned with median sagittal palne
parallel to the cassette
o Centred at the level of shoulder of the side under
examination
o Shoulders drawn backward and arms extended
to move the shoulders clear of retrosternal space

23. LORDOTIC
Used to demonstrate right
middle lobe collapse or
interlobar pleural effusion
 Patient in PA
projection,clasping the
sides of vertical bucky
patient bends backwards
at the waist(30-40 degree)

24. PENETRATION:
 Vertebral bodies and disc spaces just visible down
to T8/9 level through cardiac shadow
 Overpenetration / underpenetration

25.  Lungs appear more
darker
 Intervertebral dics spaces
are clearly seen
OVERPENETRATION

26. UNDERPENETRATED
Cardiac shadow is opaque
with no visibility of thoracic
vertebra

27. ROTATION
• Medial ends of
clavicle
equidistand from
spinous process

28.  Narrowing, displacement,
intraluminal lesions
 Midline in its upper part,then
deviates lightly to right around
aortic knuckle
 Normal coronal diameter :
25mm (males)
21mm(females)
Carina-normal angle is 60-70
degree
TRACHEA

29.  The right tracheal
margin where trachea is
in contact with lung,Can
be traced from clavicles
down to right main
bronchus
 Normal 5mm
RIGHT PARATRACHEAL STRIPE:

30. Widening occurs in :
• Mediastinal
lymphadenopathy
• Tracheal malignancy
• Mediastinal tumours
• Mediastinitis
• Pleural effusion

31. Azygos vein :
 Lies in the angle between right
main bronchus & trachea
 Should be less than 10mm
Enlarged in :
o Enlarged subcarinal nodes
o Pregnancy
o Portal hypertension
o IVC, SVC obstruction
o Right heart failure
o Constrictive pericarditis

32. MEDIASTINUM & HEART
 2/3rd of cardiac shadow lies to left anf 1/3rd lies to right
 CARDIOTHORACIC RATIO:
Maximum tansverse diameter of the heart
and maximum width of thorax at CP angle,
measured from inner edge of ribs

33. CRT=(a+b)/c
A-Right heart border to
midline
B-left heart border to midline
C-max thoracic diameter
above CP angle from inner
border of rib
 normal less than 50%(PA)
60%(AP)

34.  All borders are clearly defined except where the
heart sits on the left hemidiaphragm.
 Right Sup. Mediastinal shadow – SVC &
innominate vessels, dilated aorta
 Left sup. Mediastinal shadow – subclavian artery
above aortic knuckle

35. ANTERIOR JUNCTION LINE
• Formed by lungs meeting
anterior to ascending aorta
• 1mm thick
• Overlying tracheal
translucency
• Runs down from below
suprasternal notch slightly
JUNCTION LINES

36.  Where the lungs meet posteriorly behind the
esophagus
 Straight/curved line convex to the left
 2mm wide
 Extends from lung apices to the aortic knuckle or
POSTERIOR JUNCTION LINE

38. o Inverted hockey stick shape
o From diaphragm on left of midline up & to the
right extending to tracheobronchial angle where
the azygos V drains into IVC.
AZYGO-OESOPHAGEAL INTERFACE

40.  Formed by lung & right wall of
esophagus
 From lung apex to azygos
 Only visualised if esophagus contain
air.
PLEURO-OESOPHAGEAL STRIPE

41. • Adjacent to vertebral bodies
• Left : <10mm wide(due to descending thoracic
aorta)
• Right : <3mm
• Enlargement occurs in tortuous aorta,
osteophytes, [paravertebral hematoma ,etc.
PARASPINAL LINE

43.  Seen in babies & young children
 Triangular Sail shaped structure
 Well defined borders projecting from one or both
sides of mediastinum
THYMUS

44.  Borders may be wavy in
outline – Wave sign of
mulvey – due to
indentation by costal
cartilages
THYMIC SIGNS

45. THYMIC SNAIL SIGN
 Triangular shaped inferior
margin of normal thymus
 More commonly seen on
right

46. THYMIC NOTCH SIGN
• The inferior border
of the thymus
blends with the
border of cardiac
silhouette

47. LUNGS
 DIVIDED INTO
UPPER
MID
LOWER

52. FISSURES
MAIN FISSURES
 Separates lobes of lung;Usually incomplete allowing
collateral air drift to occur between adjacent lobes
 Visualized when the xray is tangential

53. • From the hilum to the
6th rib in the axillary
line
• Straight / slight
downward curve
HORIZONTAL/MINOR
FISSURE:

54. • Both commence
posteriorly at T4/5 level
passing through hilum
• Left is steeper finishes
5cm behind anterior
costophrenic angle
• Right ends just behind
the angle
OBLIQUE FISSURE

55.  Comma shaped with triangular base peripherally
 Always Right sided
 Forms in apex of lung
 Consists of paired folds of parietal & visceral pleura,
azygos Vein which failed to migrate
ACCESSORY FISSURES
AZYGOES FISSURE:

56.  When left sided contains an accessory hemiazygos Vein

57.  Separates apical from basal segments of lower
lobes
 Common on right side
 Resembles horizontal fissure on PA film
 Differentiated on lateral film as it runs
posteriorly from hilum
SUPERIOR ACCESSORY FISSURE

58. • As an oblique line running
cranially from cardiophrenic
angle to hilum
• Separates medial basal from
other basal segments
• Common on right side
INFERIOR ACCESSORY
FISSURE

59. • Separates lingula from
other upper lobe segments
• Rare
LEFT SIDED HORIZONTAL FISSURE

60. INFERIOR PULMONARY LIGAMENT
 Double layer of pleura extending caudally from lower
margin of inferior pulmonary vein in hilum which may or
may not attached to diaphragm and attaches lower
lobe to mediastinum
 Frequently seen in CT

61. HIDDEN AREAS
 THE APICES
 MEDIASTINUM AND HILA
 DIAPHRAGM
 BONES

63. HILA
 Left hilum higher than
right
 Clearly defined concave
lateral borders
 Similar size

64. • Pulmonary artery contribute significantly to the hilar shadow
• Left Pulmonary Artery lies above the left main bronchus
• Right Pulmonary artery is anterior to the bronchus resulting
in right hilum being lower
• Normal lymph nodes not seen

65. DIAPHRAGM
 2-3mm thick
 Right higher than left
 Due to heart depressing left side &
not due to liver pushing up the
right side
 Left is higher if stomach or splenic
flexure is distended with gas
 Difference >3cm is significant

66.  On inspiration domes are at level of 6th rib anteriorly &
at or below 10th rib posteriorly
 Upper borders clearly visualized except on left side
where heart is in contact & in cardiophrenic angles
when there are prominent fat pads
 Loss of outline – indicates adjacent lung tissue does
not contain air. eg: consolidation or pleural disease

67. Are acute & well defined
Obliterated when diaphragms are
flat
Frequently contain low density ill
defined opacity caused by fat
pads.
COSTOPHRENIC ANGLE

68. SOFT TISSUES
• Include Chest wall, shoulders & lower neck
• Breast shadows
• Skin folds – seen in old age & in babies

70. BONES
o Sternum
o Clavicles
o Scapulae

71. o Ribs:
 Pathological rib notching
seen in aortic coartation
 Central homogenous coastal
cartilage calcification in
females,curvilinear marginal
calcification in males
o Spine

72. LATERAL VIEW
• The clear spaces-Retrosternal and Retrocardiac
• Obliteration of retrosternal space : in thymoma,
aneurysms of aorta, nodal masses
• Widening : emphysema

73. VERTEBRAL TRANSLUCENCY:
o Vertebral bodies more
translucent caudally
o Loss of this is seen in
Posterior basal
consolidation

74. THANK YOU