Abstract: An immobilizing arm support is disclosed for locating a patient's arm to facilitate angulated radiographic imaging, the arm support including a flexible sheet adapted for being wrapped about the patient 3 s upper and lower arm and held in place by straps, an immobilizing strap being attached to the sheet for engagement with a table supporting the patient, an extension of the sheet being wrapped about the patient's wrist or hand for supporting and preventing rotation of the lower arm. The arm support is substantially radioluscent and preferably is formed with a pocket in the sheet for receiving a rigidifying panel to minimize flexure of the patient's arm. The immobilizing strap is preferably formed as a separate element for selective attachment and detachment with the sheet.