Radioulnar Synostosis, which is caused by fusion between the proximal ends of the radius and ulna, is an uncommon deformity of the upper extremity, caused by a failure of segmentation between the radius and ulna. During routine demonstration classes for the MBBS students we found proximal fusion between radius and ulna of two macerated bones. The proximal ends of radius and ulna were completely fused in two cases and the radial head was completely fused with radial notch of the ulna. The processes and notches of ulna were incomplete. Such anomalous fusion may lead to difficulties in daily activities, such as writing, eating, and accepting objects in an open palm. Knowledge of proximal radioulnar Synostosis is important for present day surgeon orthropedician and radiologist in interpretation of CT-scans and MRI