The sternoclavicular joint is subject to the same disease processes than the rest of the joints; it is a synovial joint. Ganglions are circumscribed tumors associated to a synovial structure; their highest incidence is in the wrist dorsum, but they may be found in all the joints with a synovial structure. The etiology of ganglions includes degenerative, traumatic, congenital causes and inflammatory processes. We describe herein the case of a 6 year old female patient with a ganglion in the sternoclavicular joint, with a traumatic origin and symptomatic upon performing physical activity. Ultrasound of the sternoclavicular joint was performed; treatment included puncture, aspiration and methylprednisolone injection. The observation of asymptomatic patients is a perfectly reasonable treatment plan.