Pediatric hand (oblique view)

Radiopaedia • CC-by-nc-sa 3.0 • de

The oblique hand view for pediatrics is part of a two view series examining the phalanges, metacarpals, carpal bones and distal radioulnar joint.

Indications

This view is useful in assessing suspected dislocations or fractures, localizing foreign bodies or evaluating juvenile idiopathic/rheumatoid arthritis of the metacarpals, phalanges and joints in the hand.

Patient position

  • patient is seated alongside the table
  • the affected arm if possible is flexed at 90° so the arm and hand can rest on the table
  • the hand is rotated externally by 45° from the basic PA position with fingers kept in extension and parallel to image receptor
  • shoulder, elbow, and wrist should all be in the transverse plane, perpendicular to the central beam
  • the hand and elbow should be at shoulder height which makes radius and ulna parallel (lowering the arm makes the radius cross the ulna, thus foreshortening the radius)

Technical factors

  • posteroanterior projection
  • centering point
    • third metacarpal head
  • collimation
    • laterally to the skin margins
    • proximal to include distal radioulnar joint; patients may have referred pain from pathology other than the hand
    • distal to the tips of the distal phalanges
  • orientation  
    • portrait
  • detector size
    • 18 cm x 24 cm
  • exposure
    • 40-48 kVp
    • 2-3 mAs
  • SID
    • 100 cm
  • grid
    • no

Image technical evaluation

Fingers are positioned parallel to image receptor, indicated by open interphalangeal and metacarpophalangeal joint spaces. Correct obliquity is evidenced by the following:

  • midshafts of 3rd to 5th metacarpals do not overlap
  • some overlap of the distal heads of the 3rd to 5th metacarpals
  • no overlap of the distal heads of the 2nd and 3rd metacarpals

Practical points

Preparing the room beforehand (setting up the detector, a small 30-45° immobilization sponge to help maintain an oblique position, exposure and preparing lead gowns) is extremely beneficial for hand imaging as young children may not remain still when their affected hand is brought away from their body.

Immobilization techniques

Ideally, if parental holding is required, the parent holds the proximal part of the child’s arm from anterolaterally in order to be in the child's direct line of sight;

  • this will require clear instructions for parents to follow, hence preventing malrotation/motion artifact from a wriggling child
  • if the parent is accompanying the child by holding them in position, whilst the parent puts on a lead gown, it is the radiographer's responsibility to ensure the child does not fall off the chair
  • if other methods can be used such as distraction techniques, this is ideal to avoid scattered radiation to parents and staff