THE FOLLOWING is a report of a case of complete rupture of the sternal portion of the pectoralis major muscle. Rupture of this muscle is an infrequent occurrence.1 Report of a Case A 41-year-old Negro laborer was admitted to the hospital complaining chiefly of a painless mass of four months' duration in the left pectoral region. Eight months prior to admission the patient suffered multiple injuries to both ankles while sliding from a seven-foot ledge with his arms placed behind him in an attempt to arrest his fall. He had no complaints involving the left shoulder. The next day he noted a painless, ecchymotic area over the left shoulder and anterior portion of the upper arm which lasted several days. It was not until four months later that he noted a mass over the left pectoral region which, according to the patient, enlarged during the following four months prior