AP OBLIQUE EXTERNAL ROTATION

Pathology demonstrated : 

Fx or dislocation of elbow (radial head and neck) Osteoarthritis and osteomyelitis 

External oblique: best visualizes radial head and neck and capitulum of humerus

IR Size : 

24*30 

IR Position :

Crosswise / Tabletop 

Sheilding :

place lead shield over patient’s lap

Patient Position :

seat pt at end of table, with arm fully extended and shoulder and elbow on same horizontal plane (lower shoulder as needed)

Part position : 

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

CR : 

CR ┴ to IR directed to midelbow joint, which is approximately 2 cm (3/4 inch) distal to midpoint of a line b/w epicondyles

Collimation :

collimate on 4 sides to area of interest

Criteria : 

Structures Shown: 

• An oblique view of the distal humerus and proximal radius and ulna is visible.

Position: 

• Long axis of arm should be aligned with side border of IR.

Correct 45° 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.