Tehran University of Medical Sciences The Research in Heart Yield and Translational Medicine (RHYTHM) 3115-7270 15 2 2020 04 30 81 83 Elif Coskun Sungur Department of Cardiovascular Surgery, Faculty of Medicine, Bulent Ecevit University, Zonguldak, Turkey. Ufuk Tütün Department of Cardiovascular Surgery, Faculty of Medicine, Bulent Ecevit University, Zonguldak, Turkey. Anıl Tekin Department of Cardiovascular Surgery, Faculty of Medicine, Bulent Ecevit University, Zonguldak, Turkey. 2018 09 25 2020 02 06 The sternal foramen is an anatomical variation at the lower third of the sternum which carries the risk of life-threatening complications such as pneumothorax. It is usually asymptomatic and can be misinterpreted as an acquired lesion. The sternum is close to the mediastinal structures; the sternal foramen, thus, leaves the lung, heart, and great vessels unprotected during invasive procedures. A 61-year-old male patient was admitted to our emergency department with sudden-onset chest pain. Acute coronary syndrome was diagnosed by the cardiology department. Coronary angiography confirmed the diagnosis of coronary artery disease, and the patient underwent urgent coronary artery bypass grafting. During the exploration, sternotomy was performed with a proper incision. Two sternal images were obtained via the median incision, and a sternal foramen was detected intraoperatively. To the best of our knowledge, this is the first case of sternotomy to undergo open-heart surgery for coronary heart disease and to be diagnosed with the sternal foramen intraoperatively. It is of vital importance that surgeons and interventionists recognize the sternal foramen, which leaves the mediastinal structures unprotected, and take early precautions. https://rhythm.tums.ac.ir/index.php/jthc/article/view/966 https://rhythm.tums.ac.ir/index.php/jthc/article/download/966/905