Digastric musculus sternalis.

PURPOSE: To report a rare variant muscle.

METHODS

Aberrant muscle was observed in the anterior chest wall musculature during routine cadaver prosection.

RESULTS

Musculus sternalis consisting of two muscular bellies united at an angle by an intermediate tendon was observed anterior to the pectoral major of the left side. The muscle did not have any bony attachment.

CONCLUSIONS

The present case represents a hybrid muscle with superior belly derived from the prepectoral mass and inferior belly from ventral longitudinal muscle column. Clinically, the musculus sternalis may be misinterpreted as a pathological mass or lesion thus its accurate knowledge is significant to radiologists, angiologists and surgeons for better interpretation of mammographic images, safer interventions and for reconstructive surgeries.