Sometimes, a 'winging scapula' reveals a disabling scapulothoracic condition. Sometimes it does not. Often, despite no observable winging, debilitating scapulothoracic conditions go undiagnosed or misdiagnosed. This "shoulder" problem is poorly understood. Disruption of essential scapular connections within the chest wall results in multiple, seemingly unrelated symptoms, obfuscating the true source of the problem. Scapular dyskinesis can masquerade as a neck problem, a back problem, a chest, head or arm problem. Current musculoskeletal assessments do not identify an isolated scapulothoracic condition unless there is obvious deformity or X-ray evidence of a fracture. In 2012, Janet Delorme, a physiotherapist with over thirty years' experience in orthopedic assessment and treatment, suffered a peculiar loss of movement and strength in her arm. Only a physiotherapist would puzzle over this problem. Her curiosity and persistence, her specialized knowledge and experience, andher unique opportunity to truly understand this problem from the "inside" has unlocked an entirely new understanding of this complex biomechanical region. This assessment method is presented in an easy-to-use format, and it can be added to an existing assessment protocol. It is designed for any clinician who has the desire to learn how to recognize and manage a condition that may otherwise go undiagnosed.