Distal Humerus and Forearm AP Projection Quiz

Distal Humerus AP Projection (Acute Flexion)

• Patient positioned at the end of the radiographic table with elbow fully flexed.
• Image receptor (IR) centered proximal to the humerus' epicondylar area.
• Long axes of the arm and forearm parallel to the IR's long axis.
• Central ray perpendicular to the humerus, approximately 2 inches superior to the olecranon process.
• Collimation adjusted to include the proximal forearm half and 1 inch beyond the olecranon process and elbow sides.
• Structures shown: proximal forearm and distal humerus. Olecranon process clearly visualized.

Proximal Forearm PA Projection (Acute Flexion)

• Center the flexed elbow joint at the corner of the IR.
• Long axes of superimposed forearm and arm parallel to the IR's long axis.
• Central ray positioned perpendicular to the humerus.

Distal Humerus AP Projection (Partial Flexion)

• Patient seated with the entire humerus on the same plane.
• Forearm supported and elevated.
• Hand is ideally supinated.
• Position the IR underneath the elbow, elevated to the condyloid area of the humerus.
• Central ray perpendicular to humerus, traversing the elbow joint. Adjust direction distally based on flexion angle.
• Collimation adjusted 3 inches proximal and distal to the elbow joint, and 1 inch on the sides.
• Visualizes the distal humerus (when elbow can't fully flex).

Proximal Forearm AP Projection (Partial Flexion)

• Similar to the distal humerus projection, but with the central ray angled perpendicular to the flexed forearm, entering approximately 2 inches distal to the olecranon process.
• The elbow joint should be more open than in a distal humerus projection.

Radial Head Lateral Projection

• Patient seated at the end of the radiographic table with hand supinated.
• Position patient high enough to place forearm on the table.
• Central ray perpendicular to the elbow joint and long axis of the forearm.
• IR positioned so it passes through the midpoint.
• Elbow flexed at 90 degrees. The elbow joint is centered on the IR and placed in lateral position.
• Four exposures: 1st - hand supinated; 2nd - hand lateral; 3rd - hand pronated; 4th - hand in extreme internal rotation.
• Visualizes the proximal forearm when elbow can't fully flex.

Radial Head and Coronoid Process Axiolateral Projection

• Humerus, elbow, and wrist joints in the same plane.
• Patient is usually supine.
• Pronate/flex elbow (90° for radial head, 80° for coronoid process).
• Center IR at elbow joint.
• Elevate distal humerus on a radiolucent sponge.
• Position IR vertically centered on the elbow joint.
• Slowly flex the elbow 90° (radial head) or 80° (coronoid process).
• Turn hand so that palmar aspect faces medially.
• Central ray directed toward the shoulder (45° to radial head in seated; cephalad at 45° to radial head in supine).
• Central ray for coronoid process directed away from the shoulder (45° to coronoid process in seated; caudad at 45° to coronoid process in supine).
• Results in open elbow joint visualizations: Radial head/capitulum and coronoid process/trochlea.