Forearm fractures are common in all age groups. Even if the adjacent joints are not directly involved, these fractures have an intra-articular character. One of the most common complications of these injuries is a painful limitation of the range of motion and especially of pronation and supination. This is often due to an underdiagnosed torsional deformity; however, in recent years new methods have been developed to make these torsional differences visible and quantifiable through the use of sectional imaging. The principle of measurement corresponds to that of the torsion measurement of the lower limbs. Computed tomography (CT) or magnetic resonance imaging (MRI) scans are created at defined heights. By searching for certain landmarks, torsional angles are measured in relation to a defined reference line. A new alternative is the use of 3D reformation models. The presence of a torsional deformity, especial of the radius, leads to an impairment of the pronation and supination of the forearm. In the presence of torsional deformities, radiological measurements can help to decide if an operation is needed or not. Unlike the lower limbs, there are still no uniform cut-off values as to when a correction is indicated. Decisions must be made together with the patient by taking the clinical and radiological results into account.

A cadaveric study of the radial head and neck was performed to determine the anterior and posterior limits for safe placement of internal fixation on the surface of the radial head or neck. A \"safe zone\" of approximately 110 degrees of radial head surface was first identified by cross-sectional anatomic dissections. This \"safe zone\" was then reproducibly confirmed relative to forearm position when viewed from a standard lateral approach. Because the proximal radioulnar joint cannot be directly visualized through the standard lateral approach, the zone was indirectly identified by making reference marks along the radial head and neck. To determine the position of the \"safe zone\" reference marks are first made along radial head and neck so as to bisect the bone\'s anteroposterior distance. Three such marks are made with the forearm in neutral rotation, full supination, and full pronation. Next, the posterior limit of the zone is determined by bisecting the reference marks made with the forearm in neutral rotation and full pronation. The anterior limit is determined by going nearly two thirds of the distance from the neutral mark to that mark made in full supination.