Lateral Humerus
The Lateral Humerus completes the evaluation of the upper arm by providing a view exactly 90 degrees from the AP projection. This “profile” is essential for determining the direction of fracture displacement—whether a bone fragment has moved anteriorly or posteriorly—which is information a single AP view simply cannot provide.
The Goal
To demonstrate the entire humerus in a true lateral position, including the shoulder and elbow joints, with the lesser tubercle profiled medially.
Patient Positioning
- The Setup: Place the patient upright with their back against the bucky or supine on the table.
- The Rotation: Flex the elbow 90 degrees and place the patient’s hand on their abdomen. This naturally rotates the humerus into a lateral position.
- The Epicondyles: The elbow epicondyles must be perpendicular to the IR.
- Trauma Variation (The “Transthoracic”): If the patient has a known fracture and cannot move their arm, do not attempt to rotate it. Instead, perform a “Transthoracic Lateral” by shooting through the patient’s chest to see the affected humerus against the IR on the opposite side.
- Pro-Tip: If the patient can move, have them slightly rotate their body toward the IR to help clear the humerus from the ribs, ensuring the entire shaft is seen in “free space”.
Technical Factors
- Central Ray (CR): Perpendicular to the IR, centered to the mid-shaft of the humerus.
- SID: 40″.
- Collimation: Must include the entire humerus, extending at least 1 inch past both the shoulder and elbow joints.
Image Evaluation Criteria (The “Richie” Checklist)
Check your Lateral Humerus against these professional standards:
- True Lateral: The elbow epicondyles should be superimposed, and the lesser tubercle should be seen in profile medially.
- Joint Inclusion: Both the shoulder and elbow joints must be fully visible on the image.
- Sharp Detail: Cortical margins should be sharp. Because the humerus is often imaged through more soft tissue in this view, ensure the patient is holding their breath to prevent blur.
- Correct Marker: Your physical R/L marker must be clear and placed in the lateral light field, away from the anatomy.
Why the Lateral Matters
In orthopedic surgery, the lateral view is the “roadmap” for hardware placement. If a patient needs an intramedullary nail or a plate, the surgeon must know the exact orientation of the fracture line. A perfectly positioned lateral humerus ensures there are no surprises once the patient is in the operating room.
Richie’s Pro-Tips for the Lateral View
Privacy & Breathing: Always ensure the patient is properly shielded and the room door is closed. Have the patient hold their breath on expiration to provide a steady, still frame for the exposure.
Watch the Elbow: A common mistake is letting the elbow “drift” away from the IR. Use a small sponge behind the elbow if necessary to keep the humerus perfectly parallel to the board.
Lead Markers are Legal: Digital markers are not an acceptable substitute for physical lead markers. In a lateral humerus, place your marker on the anterior side of the arm where there is usually plenty of light field space.
The “Complete” Standard: It is an ethical and professional violation to submit an image with a clipped joint. If the humerus is longer than your 14×17 IR, you must take two images to ensure both the shoulder and elbow are fully captured.