The lateral thumb view for pediatrics is part of a two view series examining the distal metacarpal, distal and proximal phalanges.
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Indications
This projection is useful for diagnosing fractures and localizing foreign bodies in pediatric patients. It also presents as an orthogonal view of the AP/PA thumb view.
Patient position
- patient is seated alongside the table or supine with arm outstretched
- the wrist is kept in ulnar deviation and thumb abducted
- rotate hands and curl fingers until the lateral aspect of thumb is brought into contact with the cassette
Technical factors
- lateral projection
-
centering point
- first metacarpophalangeal joint space
-
collimation
- laterally and distal to the skin margins
- proximal to the carpometacarpal joint
-
orientation
- portrait
-
detector size
- 18 cm x 24 cm
-
exposure 1
- 40-46 kVp
- 0.8-2 mAs
-
SID
- 100 cm
-
grid
- no
Image technical evaluation
Thumb is visualized with open interphalangeal and metacarpophalangeal joint spaces. A concave appearance on the anterior side of the phalanges demonstrates a true lateral position 2. The correct thumb must be correctly labeled and identified.
Practical points
Preparing the room beforehand (setting up the detector, exposure and preparing lead gowns) is important as pediatric patients may not remain still when their affected thumb is moved onto the detector.
Immobilization techniques
For this lateral view, it is particularly important to avoid superimposition of the other fingers; hence the child's parent or radiographer may need to assist in keeping other fingers still.
It is also important for the radiograph to be free from motion artifact and rotation to avoid repeated x-rays.
- it may be necessary for the parent or radiographer to hold the patient in position
- ideally the parent should be in the child's direct line of sight
- techniques will vary based on the department
- distraction techniques can be utilized to avoid scattered radiation to parents and staff 3