title: MR imaging appearances of acromioclavicular joint dislocation.
abstract: The key structures involved in dislocation of the acromioclavicular joint (ACJ) are the joint itself and the strong accessory coracoclavicular ligament. ACJ dislocations are classified with the Rockwood system, which comprises six grades of injury. Treatment planning requires accurate grading of the ACJ disruption, but correct classification can be difficult with clinical assessment. Magnetic resonance (MR) imaging has a well-established role in evaluation of ACJ pain. MR imaging performed in the coronal oblique plane parallel to the distal clavicle allows assessment of the acromioclavicular and coracoclavicular ligaments owing to its in-plane orientation in relation to these structures. This technique enables distinction between grade 2 and grade 3 injuries, which can be difficult with conventional clinical and radiographic evaluation. In addition, diagnosis of grade 1 injuries is possible by demonstration of a ruptured superiodorsal acromioclavicular ligament. Resultant thickening of the acromioclavicular or coracoclavicular ligament allows identification of chronic ACJ injuries.
authors: Department of Radiology, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, Middlesex, England. faisal_alyas@hotmail.com
authors: Faisal
authors: F
authors: Alyas
authors: Mark
authors: M
authors: Curtis
authors: Cathy
authors: C
authors: Speed
authors: Asif
authors: A
authors: Saifuddin
authors: David
authors: D
authors: Connell
mesh_terms: D000173:Acromioclavicular Joint / Q000033:anatomy & histology / Q000293:injuries*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D012783:Shoulder Dislocation / Q000175:diagnosis*