The imaging findings of a normal variant seen on mammography are presented in this article. The sternalis muscle is an uncommon normal variant, seen only in 8% of cadaveric studies. It is increasingly demonstrated with mammography as imaging techniques improve. This normal variant needs to be differentiated from significant pathology and can pose a diagnostic dilemma. In this article the anatomy of this muscle and the imaging findings are discussed. In selected cases computed tomography (CT) or magnetic resonance imaging (MRI) will be required to investigate the mammographic findings further and these modalities are described regarding the assessment of the sternalis muscle.

sternalis muscle