Luis Cerezal, MD · Francisco del Piñal, MD, PhD · Faustino Abascal, MD · Roberto Garcı´a-Valtuille, MD · Teresa Pereda, MD · Ana Canga, MD

From the Department of Radiology, Instituto Radiológico Cántabro, Clínica Mompía, Mompía, 39100 Cantabria, Spain (L.C., F.A., R.G.V., T.P., A.C.); and the Private Hand-Wrist and Plastic-Reconstructive Surgery and Hand Surgery Department, Mutua Montañesa, Rualasal, Santander, Spain ©RSNA, 2002

Abstract: Impaction syndromes related to ulnar-sided pain include ulnar impaction syndrome, ulnar impingement syndrome, ulnocarpal impaction syndrome secondary to nonunion of the ulnar styloid process, ulnar styloid impaction syndrome, and hamatolunate impingement syndrome. The most common of these, ulnar impaction syndrome, is adegenerative condition of the ulnar side of the wrist related to excessive load bearing across the ulnar carpus, triangular fibrocartilage (TFC) complex, and ulnar head. In an adequate clinical setting, characteristic osseous findings at radiography include positive ulnar variance in ulnar impaction syndrome, a short ulna in ulnar impingement syndrome, nonunion of the ulnar styloid process in ulnar impaction syndrome secondary to ulnar styloid nonunion, an excessively long ulnar styloid process in ulnar styloid impaction syndrome, and type II lunate bone in hamatolunate impingement syndrome. Nevertheless, confirmation of clinical and conventional radiographic findings with magnetic resonance (MR) imaging is often necessary to exclude other entities with similar clinical manifestations. MR imaging allows earlier detection of an abnormality in the TFC complex, cartilage, or bone marrow of carpal bones and is helpful in formulating the extensive differential diagnosis in patients with ulnar wrist pain and limitation of motion.