Sternalis muscle (SM) is an anatomical variant that lies parallel to the sternum. It is present in (8%) of human population. Awareness about its presence during thoracic imaging is important, since it might be misdiagnosed as a tumor. This study is the first that discusses the prevalence of SM in the Jordanian population and document the level of awareness about SM among intern doctors and surgery and radiology residents. Our aims are to know the prevalence of SM in the Jordanian population, using thoracic multi-detector computerized tomography (CT) images, and to assess the awareness about SM among a sample of intern and resident Jordanian physicians. Random anonymous axial thoracic multi-detector CT images of 1,709 (801 females and 908 males) Jordanian patients, were examined for the presence or absence of unilateral and/ or bilateral SM. A questionnaire aiming to identify SM was distributed among 175 intern doctors, 26 surgery resident and 28 radiology resident doctors, their answers were summarized. The prevalence of SM among Jordanians is 5.9%. The prevalence of unilateral SM is 2.1% on the right side of the thorax and 1.9% on the left side, bilateral prevalence was 1.8%. While 35.7% of the radiology residents could identify SM using CT and/or anatomy images, only 3.9% of surgery residents and none of the intern doctors could. We concluded that SM is present in the Jordanian population, with a prevalence of 5.9% which falls within the global average. Intern doctors and surgery and radiology residents are almost unaware and unfamiliar about SM.