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Case 47 

Case 47
Case 47

Catherine M. Appleton

, Kimberly N. Wiele

, and Susan Holley

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  • Triangular or “sail-shaped” density in the medial breast on the CC view (arrowhead); no correlate is present on the MLO view

    • Cleavage view demonstrates the finding to greatest advantage (arrow)

Differential Diagnosis

  • None—classic appearance demonstrated

Teaching Points

  • Normal variant of chest wall musculature

    • Muscle oriented parallel to sternum

    • No known function

  • Uncommon, less than 8% of the population

    • Occasionally seen on CC view of mammogram

  • Typically triangular, flame- or “sail-shaped,” but may appear rounded

  • If the appearance is not classic, recall the patient for a diagnostic evaluation in order to exclude a true mass


  • Annual screening mammography

Selected References/Further Reading

Bassett LW, et al. Diagnosis of Diseases of the Breast, 2nd ed. Philadelphia: WB Saunders Co., 2005:393-395.Find this resource:

    Bradley FM, et al. The sternalis muscle: An unusual normal finding seen on mammography. AJR 1996;166:33-36.Find this resource:

    Ikeda DM. Breast Imaging: The Requisites. Philadelphia: Elsevier Mosby, 2004:26-27.Find this resource: