The thoracic cage is formed by the sternum anteriorly, twelve pairs of ribs, and twelve thoracic vertebrae. The ribs are classified as true ribs, false ribs, or floating ribs depending on their attachment to the sternum or vertebrae. Various x-ray projections are used to image different regions of the thoracic cage, including anteroposterior, oblique, and lateral views. Patient positioning and centering of the x-ray beam are important to visualize the desired anatomical structures while minimizing overlap.

2. THORACIC CAGE
The thorax (thoracic cage) is formed by the sternum anteriorly,
twelve pairs of ribs forming the lateral bony cages, and the twelve
thoracic vertebrae.

4. THE RIBS
 The 12 pairs of ribs form the lateral walls of the thoracic cage.
 There are classified as three types. such us
1) True ribs
2) False ribs
3) Floating ribs
 Anteriorly, the first seven pairs of ribs articulate directly with the
sternum and are known as the True ribs.

5.  The next three pairs (False ribs) articulate only indirectly.
In both cases, costal cartilages attach the ribs to the sternum.
 The lowest two pairs of ribs, referred to as Floating Ribs, do
not join the sternum at all, their anterior tips being free.
 The first rib is firmly fixed to the sternum and to the 1st
thoracic vertebra, and does not move during inspiration.

7.  This flat bone can be felt just under the skin in the middle of
the front of the chest.
 The manubrium is the uppermost section and articulates with
the clavicles at the sternoclavicular joints and with the first two
pairs of ribs.
 The body or middle portion gives attachment to the ribs.
 The xiphoid process is the inferior tip of the bone.
 It gives attachment to the diaphragm, muscles of the anterior
abdominal wall and the linea alba

9. LOWER RIBS
1) Antero-posterior Projection
2) Right and left posterior oblique
UPPER RIBS
1) Right and left posterior oblique
2) First and second – anteroposterior

10. LOWER RIBS
1) ANTERO-POSTERIOR PROJECTION
 A cassette is selected that is large enough to include the whole of
the right and left sides, from the level of the middle of the body
of the sternum to the lower costal margin.
 The cassette is placed in the Bucky tray.

11. POSITION OF PATIENT AND CASSETTE
 The patient lies supine on the imaging , with the median sagittal
plane coincident with the midline of the couch and Bucky
mechanism.
 The anterior superior iliac spines should be equidistant from the
couch top.
 The cassette is placed transversely, with its caudal edge
positioned at a level just below the lower costal margin.

12. ANTERO-POSTERIOR PROJECTION

13. DIRECTION AND CENTRING OF THE X-RAY BEAM
• The vertical central ray is centred in the midline at the level of
the lower costal margin and then angled cranially to coincide with
the centre of the film.
• This centring assists in demonstrating the maximum number of
ribs below the diaphragm.
• Exposure made on full expiration will also assist in this
objective.

14. 2) RIGHT AND LEFT POSTERIOR OBLIQUE
A 35 X 43-cm cassette is selected to include either the right or the
left lower rib sides. The patient may be examined erect or supine
using a Bucky grid.
POSITION OF PATIENT AND CASSETTE
• The patient lies supine on the Bucky table or stands erect, with the
midclavicular line of the side under examination coincident with the
midline of the Bucky grid.

15. • The trunk is rotated 45 degrees on to the side being examined,
with the raised side supported on non-opaque pads.
• The hips and knees are flexed for comfort and to assist in
maintaining patient position.
• The caudal edge of the cassette is positioned at a level just below
the lower costal margin.
• The cassette should be large enough to include the ribs.

16. RIGHT AND LEFT POSTERIOR OBLIQUE

17. DIRECTION AND CENTRING OF THE X-RAY BEAM
• The vertical central ray is directed to the midline of the anterior
surface of the patient, at the level of the lower costal margin.
• From this position, the central ray is then angled cranially to
coincide with the centre of the cassette.
• Exposure is made on arrested full expiration.

18. NOTES
• The patient may find it difficult to maintain this position if they
are in a great deal of pain.
• Selection of a short exposure time and rehearsal of the breathing
technique may be necessary to reduce the risk of movement
unsharpness.

19. UPPER RIBS
1) RIGHT AND LEFT POSTERIOR OBLIQUE
 Radiography may be conducted with the patient erect or supine.
 A cassette is selected that is large enough to include the whole of
the ribs on the side being examined from the level of the seventh
cervical vertebra to the lower costal margin.

20. POSITION OF PATIENT AND CASSETTE
• The patient sits or stands with the posterior aspect of the trunk
against the vertical Bucky. Alternatively, the patient lies supine on
the Bucky table.
• The midclavicular line of the side under examination should
coincide with the central line of the Bucky or table.
• The trunk is rotated 45 degrees towards the side being examined
and, if supine, is supported on non-opaque pads.

21. • The patient’s hands should be clasped behind the head, otherwise
the arms should be held clear of the trunk.
• The cranial edge of the cassette should be positioned at a level just
above the spinous process of the seventh cervical vertebra.
NOTE
The kVp should be sufficient to reduce the difference in subject
contrast between the lung fields and the heart to a more uniform
radiographic contrast so that the ribs are visualized adequately in
both these areas.

22. RIGHT AND LEFT POSTERIOR
OBLIQUE

23. DIRECTION AND CENTRING OF THE X-RAY BEAM
• Initially, direct the central ray perpendicular to the cassette and
towards the sternal angle.
• Then angle the beam caudally so that the central ray coincides
with the centre of the cassette.
• Exposure made on arrested full inspiration will also assist in
maximizing the number of ribs demonstrated.

24. 2) FIRST AND SECOND ANTERO-POSTERIOR
 The first and second ribs are often superimposed upon each other.
 A separate projection may be necessary to demonstrate them
adequately.
 An 18 X 24-cm or 24 X 30-cm cassette fitted with standard-
speed screens is selected.

25. POSITION OF PATIENT AND CASSETTE
• The patient lies supine on the table or stands with the posterior
aspect of the trunk against a cassette.
• When the patient is erect, the cassette is placed in a cassette holder
attachment.
• The median sagittal plane is adjusted at right-angles to the cassette.
• The cassette is centred to the junction of the medial and middle
thirds of the clavicle.

26. FIRST AND SECOND ANTERO-
POSTERIOR

27. DIRECTION AND CENTRING OF THE X-RAY
BEAM
• Direct the central ray perpendicular to the cassette and towards
the junction of the medial and middle thirds of the clavicle.
• Direct the central ray perpendicular to the cassette and towards
the junction of the medial and middle thirds of the clavicle.

28. 1) Anterior oblique – tube angled
2) Anterior oblique – trunk rotated
3) Lateral

29. 1) ANTERIOR OBLIQUE – TUBE ANGLED
 The patient prone or erect, with the sternum at a minimal distance
from the image receptor to reduce unsharpness.
 However, if the patient has sustained a major injury to the
sternum, then they may not be able to adopt the prone position
due to pain.
 A 24 X 30-cm grid cassette fitted with standard-speed screens is
selected.

30. POSITION OF PATIENT AND CASSETTE
• The patient stands or sits facing the vertical Bucky or lies prone on
the table.
• The medial sagittal plane should be at right-angles to, and centred
to, the cassette.
• As the central ray is to be angled across the table, the cassette is
placed transversely to avoid grid cut-off.

31. ANTERIOR OBLIQUE – TUBE
ANGLED

32. • If the Bucky is to be used on the table, the patient should lie on a
trolley positioned at right-angles to the table, with the thorax
resting on the Bucky table.
• The cassette is centred at the level of the fifth thoracic vertebra.
• Immobilization will be assisted if it is possible to use an
immobilization band.

33. DIRECTION AND CENTRING OF THE X-RAY
BEAM
• The perpendicular central ray is centred initially to the axilla of
either side at the level of the fifth thoracic vertebra.
• The central ray is then angled transversely so that the central
ray is directed to a point 7.5cm lateral to the midline on the same
side.

34. NOTES
• The patient is allowed to breathe gently during an exposure
time of several seconds using a low mA.
• This technique diffuses the lung and rib shadows, which
otherwise tend to obscure the sternum.

35. 2) ANTERIOR OBLIQUE – TRUNK ROTATED
A 24 X 30-cm cassette is selected for use in the Bucky mechanism.
Alternatively, a grid cassette may be used in the vertical cassette
holder.
POSITION OF PATIENT AND CASSETTE
• The patient initially sits or stands facing the vertical Bucky or lies
prone on the Bucky table with the median sagittal plane at right-
angles to, and centred to, the cassette.

36. • The patient is then rotated approximately 20–30 degrees, with the
right side raised to adopt the left anterior oblique position, which
will ensure that less heart shadow obscures the sternum.
• The patient is supported in position with non-opaque pads and an
immobilization band where possible.
• The cassette is centred at the level of the fifth thoracic vertebra.

37. ANTERIOR OBLIQUE – TRUNK
ROTATED

38. DIRECTION AND CENTRING OF THE X-RAY BEAM
• Direct the central ray perpendicular to the cassette and towards a
point 7.5cm lateral to the fifth thoracic vertebra on the side nearest
the X-ray tube.
NOTE
The patient is allowed to breathe gently during an exposure time of
several seconds using a low mA, provided that immobilization is
adequate.

39. 3) STERNUM - LATERAL
A 24 X 30-cm grid cassette fitted with standard-speed screens is
selected. Alternatively a cassette may be used in the vertical Bucky.
POSITION OF PATIENT AND CASSETTE
• The patient sits or stands, with either shoulder against a vertical
Bucky or cassette stand.
• The median sagittal plane of the trunk is adjusted parallel to the
cassette.

40. STERNUM - LATERAL

41. • The sternum is centred to the cassette or Bucky.
• The patient’s hands are clasped behind the back.
• The cassette is centred at a level 2.5cm below the sternal angle.
DIRECTION AND CENTRING OF THE X-RAY BEAM
• Direct the horizontal central ray towards a point 2.5cm below the
sternal angle.
• Exposure is made on arrested full inspiration.

42. NOTES
• Immediately before exposure, the patient is asked to pull back
the shoulders.
• If the patient is standing, the feet should be separated to aid
stability.
• An FFD of 120 or 150cm is selected.

43. THANK YOU……