A 9 month old cockapoo dog presented to Camell University's small animal orthopedic surgery service for evaluation of a right thoracic limb lameness of 3 to 4 months duration. After a number of trials of medical management and rest recommended by the primary and orthopedic veterinary specialist proved to be unsuccessful, advanced imaging (MRI) of the right shoulder and possible surgical correction at Cornell University was recommended. Orthopedic examination localized the patient's lameness to the right shoulder and revealed moderate pain on flexion, extension and palpation of that joint. Examination also revealed moderate diffuse muscle atrophy over the scapula, shoulder and proximal brachium. This paper will provide an overview on the diagnostic steps to localize lameness as well as different imaging modalities (specifically MRI) and diagnostic procedmes performed to help rule in or rule out different shoulder pathologies.