The plain radiograph shown above is taken with the forearm in approximately 20 degrees of forearm pronation, which allows the entire periphery of the trapezium to be seen.
Reproduced from: Upper Limb. In: Merrill's Atlas of Radiographic Positioning and Procedures, 2nd ed, Frank ED, Long BW, Smith BJ (Eds), Elsevier, St. Louis 2011. Illustration used with the permission of Elsevier Inc. All rights reserved.