Abstract

The forearm consists of the radius and ulna which are connected by the proximal and distal radioulnar joints, the interosseous membrane and several muscles. Forearm rotation, consisting of pronation and supination, is a rotatory motion of the radius around the ulna in combination with subtle translation1. The longitudinal axis of the forearm is considered to pass through the centre of the radial head proximally and through the ulnar fovea at the base of the ulnar styloid distally2. Forearm rotation is commonly used in daily life; whereas pronation is used for writing and typing, movements such as perineal hygiene and accepting monetary change require supination. In children up to the age of 15 years, pronation of 50-80 degrees and supination of 80-120 degrees are considered normal3. Furthermore a limitation of forearm rotation only affects daily activities if pronation or supination is less than 50 degrees4, because the ipsilateral shoulder can compensate mild limitation of pronation by abduction and internal rotation, and mild limitation of supination by adduction and external rotation. In a number of pathologies forearm rotation can be limited, such as following a forearm fracture. Forearm fractures represent one of the most common fractures in children; a distinction is made between fractures of the radius or the ulna only, and fractures of both the radius and ulna. Furthermore, a differentiation is made between incomplete fractures typical for children (torus, greenstick and bowing) and complete fractures that occur in children as well as in adults. The treatment of these both-bone forearm fractures depends on anatomical location (proximal metaphysis, distal metaphysis or diaphysis) and fracture displacement (minimally displaced or severely displaced).