Unilateral sternal muscle in an adult melanodermic cadaver

Abstract

The sternal muscle, also known as sternalis, rectussternal, parasternal or japonicus is a curious case of anatomical variation of the anterior chest wall. During a routine dissection, a muscle mass related to the sternum was found in the anterior wall of the right hemithorax in a melanodermic female cadaver. The literature, its incidence is mentioned to vary from 3.1 to 23.5%, and little is known about its function with divergences regarding its origin, insertion, innervation and vascularization. Clinically, some mastologists report that this finding is often confused with a tumor, making it difficult to distinguish between normal structures or lesions that symbolize cancer.