It demonstrates an autosomal dominant pattern of inheritance with no sex predilection and is bilateral in 60-80% of cases. Management is conservative. The supracondylar process of the humerus occurs in approximately one percent of patients. It is often seen in early childhood when they present with functional impairments. Congenital radioulnar synostosis is a rare anomaly of the forearm with restrictions of full movement of the affected limbs. Congenital radioulnar synostosis is a rare disorder resulting in the fusion of the radius and ulna from birth. A 10-year-old female with progressive difficulty with supination in both upper limbs seen in the OPD had bilateral forearm xray which showed bilateral proximal radioulnar synostosis. failure of differentiation results in synostosis in proximal aspect of the forearm; Epidemiology This bony spur projects anteriorly and toward the elbow, 5–7 cm above the medial epicondyle (Fig. Congenital radioulnar synostosis may be associated with other musculoskeletal abnormalities such as congenital hip dislocation, clubfeet, or diminutive or supernumerary thumb. - type I, proximal or true radioulnar synostosis, in which the radius and the ulna are smoothly fused at their proximal borders for a variable distance, usually 2-6 cm, and - type II, secondary or radioulnar synostosis associated with congenital dislocation of the radial head, in which the fusion is just distal to the proximal radial epiphysis (1). Operative treatment rarely succeeds. PDF | Congenital radioulnar synostosis is a rare anomaly of the forearm with restrictions of full movement of the affected limbs. Bilateral congenital radioulnar synostosis | Radiology Case | Radiopaedia.org Congenital radioulnar synostosis is the most common congenital functional disorder of the elbow. Introduction: Definition bony bridge between the proximal radius and ulna; Etiology forearm begins as a single cartilaginous anlage and divides from distal to proximal into the radius and ulna in the 7th week in utero . Congenital radioulnar synostosis is a rare congenital bone abnormality that is bilateral in 60% of cases and appears clinically as a mild deformity in early life but with a delayed presentation.