Oblique Wrist

The Oblique Wrist is a vital bridge between the flat PA view and the true lateral. By rotating the wrist 45 degrees, you move the carpal bones—particularly the scaphoid and the trapezium—out of superimposition. This “perspective” is often the only way to detect subtle fractures in the carpal bones that would otherwise be hidden by the overlap of the radius and ulna.

The Goal

To demonstrate the carpal bones in a 45° lateral rotation, ensuring the carpals on the radial side (thumb side) are clearly visualized without excessive superimposition.

Patient Positioning

The Setup: Seat the patient at the end of the table with the shoulder, elbow, and wrist on the same horizontal plane.
The Rotation: From the PA position, rotate the entire hand and wrist laterally (thumb side up) exactly 45 degrees.
The Richie “Support” Trick: While you can ask the patient to hold this position, the wrist is naturally unstable at 45 degrees. Pull the thumb and pointer finger together to form a loose reverse “C” shape if you don’t have a 45 degree positioning sponge
Pro-Tip: Always use a 45° foam wedge sponge. Placing the wedge under the thumb side of the hand ensures the wrist stays at a true, consistent 45-degree angle throughout the exposure, preventing “fuzzy” images caused by the patient’s hand drifting.

Technical Factors

Central Ray (CR): Perpendicular to the mid-carpal area.
SID: 40″.
Collimation: Include the distal radius and ulna, all carpal bones, and the proximal half of the metacarpals.

Image Evaluation Criteria (The “Richie” Checklist)

A diagnostic Oblique Wrist must meet these specific standards:

45° Rotation: The scaphoid and the trapezium should be well-demonstrated with minimal overlap.
Complete Anatomy: You must see the distal 1/3 of the forearm down through the mid-metacarpals.
No Motion: Look for sharp cortical margins and clear trabecular detail. If the image looks “soft,” the patient moved.
Anatomically Correct Marker: Your physical R/L marker must be clear, visible, and placed within the light field away from the bone.

Why the Oblique Matters

This view is particularly critical for evaluating the scaphoid. Because the scaphoid is angled within the wrist, a flat PA often hides fractures in its “waist.” The 45-degree oblique rotation elongates the bone and provides a clearer view of its cortex. Remember: missing this view or settling for a “near-oblique” can lead to a missed diagnosis of a fracture that could cause permanent joint damage.

Richie’s Pro-Tips for the Oblique View

Professional Presence: Keep the room dim to see your crosshairs clearly, but always ensure the patient feels safe and informed. Explain that this specific angle is the “key” to seeing the small bones of their wrist correctly.

Watch the Fingers: Instruct the patient to let their fingers rest naturally against the sponge or the IR. Tensing the fingers can cause the wrist to “lift” off the board, creating unwanted magnification.

Physical Markers Only: As with all extremity work, digital markers are unacceptable. Use your physical lead markers to ensure the exam is legally and medically sound.

The “Incomplete” Rule: It is a violation of ethical standards and potentially fraudulent to submit an exam where anatomy is clipped. If you miss the proximal metacarpals, it is an incomplete study and must be repeated.