Elbow : AP Oblique

X-ray of the Elbow : AP Oblique View - Lateral or External Rotation

Radiographic examination of the elbow, oblique view and arm rotated externally this projection best demonstrate the radial head and neck and the capitulum of the humerus.
Fracture and/or dislocation of the elbow, primarily the radial head and neck, and some pathologic processes, such as osteomyelitis and arthritis, are demonstrated.

Technical Factors

IR size - 24 x 30 cm (10 x 12 inches)
Detail screen, tabletop, division in half, crosswise
Digital IR - use lead masking
60 or add upto 6kV range

Shielding and Patient Position

Place lead shield over patient's lap to protect gonads
Seat patient at end of table, with arm fully extended and shoulder and elbow on same horizontal plane (lowering shoulder as needed).

Part Position

Align arm and forearm with long axis of portion of IR that is being exposed.
Center elbow joint to CR and to portion of IR being exposed.
Supinate hand rotate laterally the entire arm so that the distal humerus and the anterior surface of the elbow joint are approximately 45degrees to cassette. (Patient must lean laterally for sufficient lateral rotation.) Palpate epicondyles to determine approximately 45degrees rotation of distal humerus.

Central Ray and Collimation

CR perpendicular to IR, directed to mid elbow joint (a point apprximately 2cm [3/4 inch] distal to midpoint of line between the epicondyles as viewed from the x-ray tube)
Minimum SID of 40 inches (100 cm)
Collimate on four sides to area of interest.

Radiographic Criteria : Oblique View of Elbow Arm Rotated Laterally

Correst Patient Positioning and Structure Shown

Long axis of arm should be aligned with side border of IR.
Correct 45degrees lateral oblique should visualize the radial head, neck, and tuberosity, free of superimposition by ulna.
The lateral epicondyle and capitulum should appear elongated and in profile.
An oblique projection of the distal humerus and proximal radius and ulna is visible.

Collimation and CR

Collimation should be visible on four sides to area of affected elbow
CR and center of collimation field should be to mid elbow joint.

Exposure Criteria

Optimal density and contrast with no motion should visualize soft tissue detail and sharp, bony cortical margins with clear, bony trabecular markings.