Chest (lateral view)

The lateral chest view is part ofmay be performed as an adjunct to a common radiological investigation of thefrontal chest radiographin the emergency department ¹cases where there is diagnostic uncertainty. The lateral chest view examines the lungs, bony thoracic cavity, mediastinum, and great vessels.

Although the PA chest view is the primary view Lateral radiographs can be particularly useful in chest imaging, the lateral radiograph is frequently used to visualiseassessing the retrosternal and retrocardiac airspace as well at the posterior structures of the lung that are obscured in the PA viewairspaces.

Patient position

• patient is erect with the standing upright
• left side of the thorax adjacent to the image receptor
  • left shoulder placed firmly against the image receptor
• both arms are raised above the head to prevent any, preventing superimposition over the chest; the
  • arms can be placed on the head or holding onto handles, if they are available
• chin is raised as to be out of the image field
• left shoulder is placed firm against the image receptor
• patient is standing upright
• midsagittal plane must be perpendicular to the divergent beam, therefore:
  • patient's right side is rotated 5-10° anterior

Technical factors

• lateral projection
• suspended inspiration  
• centring point
  • the midcoronal plane of the level of the 7^th thoracic vertebra, approximately the inferior angle of the scapulae  
• collimation
  • superiorly 5 cm above the shoulder joint to allow proper visualisation of the upper airways 
  • inferior to the inferior border of the 12^th rib 
  • anteroposterior to the level of the acromioclavicular joints
• orientation
  • portrait 
• detector size
  • 35 cm x 43 cm 
• exposure
  • 100-110 kVp
  • 8-12 mAs
• SID
  • 180 cm
• grid
  • yes 

Image technical evaluation 

The entire lung fields should be visible superior from the apices inferior to the posterior costophrenic angle 

• the chin should not be superimposing any structures 
• there is superimposition of the anterior ribs 
• the sternum is seen in profile 
• superimposition of the posterior costophrenic recess
• a minimum of ten posterior ribs are visualised above the diaphragm
• the ribs and thoracic cage are seen only faintly over the heart
• clear vascular markings of the lungs should be visible

Practical points

The left lateral is the preferred lateral position as it demonstrates better anatomical detail of the heart. 

The same principle of positioning can be applied to patients in a chair.

Before exposing ensure your patient is not leaning forward or backward too much, this will result in anatomy being cut off.

Patients with a longstanding history of emphysema or COPD will have abnormally long lungs compared to the general population, remember this when collimating superior to inferior.

Side marker placement is imperative; patients can have congenital conditions that mimic a mirrored image ². 

Patients with scoliosis may not demonstrate the traditional indicators of a correctly positioned lateral radiograph; it is important to note that patients with this condition particularly in the thoracic region will appear rotated by conventional evaluation, yet this is not the case. 

Remember to explain to your patient what you are about to do; that is, ask them to take a breath in and hold it. Many times this gives the patient time to prepare and results in a better breath hold and therefore a higher quality radiograph.

Always remember to tell your patient to breathe again!