Septic Arthritis of the Sternoclavicular Joint Manifesting as Sternocleidomastoid Muscle Abscess: A Case Report.

Septic arthritis of the sternoclavicular joint is a rare infection with an insidious onset. It often presents as chest wall swelling. Despite its proximity to vital thoracic and cervical structures, extension of infection beyond the sternoclavicular joint is uncommon. Among the rare complications, the development of a neck abscess is extremely unusual. Awareness of such atypical presentation should be emphasized. We present a case of sternocleidomastoid muscle abscess that was preceded by septic arthritis of the sternoclavicular joint in an elderly patient with diabetes.