Thumb : Lateral Projection

X-ray of the Thumb : Lateral View

It is an x-ray examination of the thumb in lateral position thumb. Radiologic Technician performs this projection as requested by Physician ofcourse, to show phatologic processes like osteoporosis and osteoarthritis, dislocations of distal to proximal phalanges of thumb and other associate joints. When collimating the tube remember that the 1st metacarpal is the entire thumb.

Pathology Demonstrated:

Lateral Position : Sponges Provided

Fracture and/or dislocation of the distal and proximal phalanges, distal metacarpal, and associated joints are shown. Some pathologic processes, such as osteoporosis and osteoarthritis, also may be demonstrated.

Technical Factors:

IR size - 18 x 24 cm (8 x 10 inches)
Division in thirds crosswise
Detail screen, table top
Digital IR-use lead masking
50 to 60 kV range

Patient Position and Shielding

Seat patient at end of table, with elbow flexed about 90degrees with hand resting on cassette, palm down.
Place lead shield over patient's lap to shield gonads.

Part Position:  

Start with hand pronated and thumb abducted, wit fingers and hand slightly arched; then rotate hand slightly medial until thumb is in a true lateral position. (may need to provide sponge or other support under lateral portion of hands.)
Align long axis of thumb with long axis of portion of IR that is being exposed.

Lateral Thumb

Center first MCP joint to CR and to center of portion of IR being exposed.
Entire lateral aspect of thumb should be in direct contact with cassette.

Central Ray:

CR perpendicular to IR, directed to first MCP joint
Minimum SID of 40 inches (100cm)

Collimation:

Collimate on four sides to thumb area. (remember that thumb includes entire first metacarpal.)