Thumb lateral view
The thumb lateral view is an orthogonal projection to AP/PA view and helps in the localization of a foreign body in the thenar eminence.
- patient is seated alongside the table
- forearm is placed on table
- the wrist is kept in ulnar deviation and thumb abducted
- lateral aspect of thumb is brought in contact with the cassette by curling fingers (see Figure 1)
X-ray beam features
To include entire thumb and carpometacarpal joint, centring approximately over the metacarpophalangeal joint space.
Marker Placement: AP, distal and anterior
Exposure Factors: 45 kV, 1.6 mAs
These are average exposures using a Siemens DR system. Exposures may vary between different CR or DR systems and with different patient body habitus.
Appropriate collimation has been utilized with the entire first digit is visualized, including the carpometacarpal (CMC) joint.
1st digit is positioned laterally, evidenced by open joint spaces and superimposition of the phalangeal and metacarpal heads. There is slight superimposition of the base of the 2nd metacarpal over the base of the 1st metacarpal, which is not ideal.
Appropriate exposure evidenced by adequate bony detail visible in entire thumb, with soft tissue visualized clearly.