- These are special projection taken for pathologic processes of trauma to the area of the radial head and / or the coronoid process of ulna. These are effective projections when patient cannot extend elbow fully for medial or lateral obliques of the elbow.
Pathology Demonstrated:
- Fractures and dislocations of the elbow, particularly the radial head (part position 1) and coronoid process (part position 2), are shown.
Technical Factors:
- IR size - 18 x 24 cm (8 x 10 inches), crosswise
- Detail screen, tabletop
- Digital IR - use lead masking
- 70 to +- 6kV range (see note)
Shielding:
- Place lead shield over gonadal area.
Patient Position:
- Seat patient at the end of the table for erect position or supine on the table for cross imaging.
Part Position:
- Elbow flexed 90degree if possible; hand pronated
- CR directed at a 45degree angle toward shoulder, centered to radial head (mid elbow joint)
- Minimum SID 40 inches (100cm)
Part Position 2 - Coronoid Process
- Elbow flexed only 80degree from extended position (because more than 80degree may obscure coronoid process) and hand pronated
- CR angled 45degree from shoulder, into mid elbow joint
- Minimum SID of 40 inches (100cm)
Collimation:
- Collimate on four sides to area of interest.
Note:
- Increase exposure factor by 4 to 6 kV from lateral elbow because of angled CR. These projection are effective with or without a splint.
Radiographic Criteria for Specific Anatomy:
For Radial Head:
- The joint space between radial head and capitulum should be ooen and clear.
- The radial head, neck, and tuberosity should be in profile and free of superimposition, except for a small part of the coronoid process.
- The distal humerus and epicondyles appear distorted because of the 45degree angle.
For Coronoid Process:
- The distal [anterior] portion of the coronoid appears elongated but in profile.
- The joint space between coronoid process and trochlea should be open and clear.
- The radial head and neck should be superimposed be ulna.
- Optimal exposure factors should visualize clearly the coronoid process in profile. Bony margins of superimposed radial head and neck should be visualized faintly through the proximal ulna.
