Pediatric elbow (horizontal beam lateral view)

The horizontal beam lateral elbow view for pediatrics is an alternative projection to the lateral view in the elbow series, examining the distal humerus, proximal radius and ulna. 

Indications

This view demonstrates an orthogonal view of the AP elbow and is ideal for patients who are unable to move their arm as per the standard elbow positioning technique. It demonstrates any joint effusion, suspected dislocations or fractures in the elbow joint.

Patient position

• patient stands or sits with back touching the upright detector (see Figure 1)
• at 90° elbow flexion, ensure all aspects of the arm from the wrist to the humerus are parallel with the detector
• rotate the hand so the thumb is perpendicular to the X-ray beam

Technical factors

• lateral projection
• centering point
  • lateral epicondyle of the humerus
• collimation
  • superior to distal third of the humerus 
  • inferior to include one-third of the proximal radius and ulna
  • anterior to include the skin margin
  • posterior to skin margin
• orientation  
  • landscape
• detector size
  • 18 cm x 24 cm
• exposure ¹
  • 50-57 kVp
  • 2-3 mAs
• SID
  • 110 cm
• grid
  • no

Image technical evaluation

• there is a superimposed, concentric relationship of the trochlear groove (smallest circle) and the medial lip of the trochlea with the capitellum
• elbow joint is open; radial tuberosity is superimposed by radius and not demonstrated in profile
• anterior half of the radial head is superimposed over the coronoid process

Practical points

Preparing the room beforehand (setting up the detector, exposure and preparing lead gowns) is extremely beneficial for elbow imaging as young children may begin to cry the moment their affected arm is brought away from their body.

Allowing the patient to use their unaffected arm to support the distal portion of their affected elbow may be helpful in ensuring 90° elbow flexion.

As with trauma imaging, preparing the room for a horizontal beam image may not always be the first line of action. Having clear positioning instructions prepared and all immobilization devices (i.e. detector holder) within reach may be useful in obtaining the image efficiently.

Immobilization techniques

To prevent malrotation/motion artifact in the radiograph, parental holding at the proximal half of the child’s arm and distal half of the forearm may be required.

• if the parent is accompanying the child, whilst the parent puts on a lead gown, it is the radiographer's responsibility to ensure the child does not fall off the chair
• other alternative methods such as distraction techniques may be ideal to avoid scattered radiation to parents and staff ²