Thumb : PA Oblique

PA projection of the Thumb in oblique view rotated medially.

Pathology Demonstrated:

• 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 24cm (8 x 10 inches)
• Division in third crosswise
• Detail screen, tabletop
• Digital IR - use lead masking
• 50 to 60 kV range

PA Oblique Rotated Medially

Shielding:

• Place lead shield over patient's lap to shield gonads.

Patient Position:

• Seat patient at end of table, with elbow flexed about 90degrees with hand resting on casstte.

Part Position:

• Abduct thumb slightly with palmar surface of hand in contact with cassette. (This action naturally places thumb in a 45degrees oblique position.)
• Align long axis of thumb with long axis of third of IR that is being exposed.
• Center first MCP joint to CR and to center of portion of IR being exposed.

Central Ray:

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

Collimation:

• Collimate on four sides to thumb, ensuring that all of first metacarpal is included.