3 Thoracic Cage

UPPER RIBS

• Right or left posterior obliques

• Lower ribs – AP

STERNUM

• Lateral

• Anterior oblique (RAO)

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UPPER RIBS

Projection: RIGHT OR LEFT POSTERIOR OBLIQUES

Centring Point: In the mid-clavicular line of the side under examination – at level of the midpoint of the sternal body. Horizontal central ray

Projection: LOWER RIBS – AP

Centring Point: To a point in the midline midway between the xiphisternum and the lower costal margin

Points to consider

Technique

Trauma – oblique ribs not always necessary – rarely changes management of the patient

Oblique – exposure on arrested full inspiration

Oblique – patient erect – better with inspiration

AP – exposure on arrested expiration to show the maximum number of ribs below the diaphragm

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Radiological assessment

Check each rib for # – it is rare to see displacement due to the numerous attached muscles

Oblique – ribs away from cassette will be foreshortened

Oblique – posterior rib articulations seen well on the raised side

#s of ribs will unite spontaneously – treatment is limited

Look for metastatic deposits – associated with rib destruction

Right or left posterior obliques

• Patient supine or erect, facing the X-ray tube

• Body rotated approximately 45° onto the affected side

• Arms are abducted away from the trunk

Collimation

To include: SUPERIORLY: First rib

INFERIORLY: Diaphragms

LATERALLY: Rib cage

Lower ribs – AP

• Patient lies supine on the X-ray table

• Shoulders and anterior superior iliac spines (ASIS) equidistant from the table top

Collimation

To include: SUPERIORLY: Diaphragms

INFERIORLY: Lower costal margin

LATERALLY: Rib cage and abdominal wall

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STERNUM

Projection: LATERAL

Centring Point: To a point 3 cm below the sternal angle. Horizontal central ray. SID 150 cm

Projection: ANTERIOR OBLIQUE (RAO)

Centring Point: To a point 8 cm lateral to the palpable fifth thoracic vertebra on the side furthest from the cassette. Horizontal central ray

Points to consider

Technique

A grid or bucky is essential for both projections

Lateral – exposure on arrested full inspiration

Lateral – greater SID of 150 cm will decrease magnification

Oblique – patient allowed to breathe gently during exposure

Right anterior oblique – cardiac shadow will help visualise the sternum

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Radiological assessment

Must include from the sternoclavicular joint to xiphisternum

Sternum must not be overpenetrated

Gentle breathing will blur the rib shadows

Obliquity – the spine and sternum must not be superimposed

Over-rotation – sternum outside cardiac shadow

Lateral

• Patient erect

• Median sagittal plane is parallel to the erect bucky

• Patient’s shoulders are rotated posteriorly

• Arms placed behind the trunk and shoulders and gently pulled back

Collimation

To include: SUPERIORLY: Acromioclavicular joints

INFERIORLY: Xiphisternum

ANTERIORLY: Anterior soft tissues

POSTERIORLY: Posterior sternum

Anterior oblique (RAO)

• Patient erect facing the cassette

• Trunk is rotated approximately 30° so that the right side of the body is in contact with the erect bucky

• Arms are placed around the erect bucky to maintain stability

Collimation

To include: SUPERIORLY: Acromioclavicular joints

INFERIORLY: Xiphisternum

LATERALLY: Costal cartilage

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