The sternalis muscle: A rare anatomical variation that can be encountered during breast reconstruction

Purpose: The sternalis muscle is a rare supernumerary muscle, located superficial to the sternum and the sternocostal fascicles of the pectoralis major. Although its frequency is rare, this muscle is significant in that it can confuse the operator during breast reconstruction. However, many clinicians, including surgeons, have not known about this anatomic variation. Therefore, we would like to report on the sternalis muscle found during breast surgery using a tissue expander to share information about this muscle and to expand the anatomy-based academic scope. Case Report: A 55-year-old female patient underwent simple mastectomy with sentinel lymph node biopsy in a left breast with invasive ductal carcinoma and followed by reconstruction using a tissue expander. Surgical findings of the pectoralis major muscle; sternalis muscle and prominence of 3rd rib were observed through the subcutaneous pocket of the left breast after removal of the breast tissue. Discussion: The sternalis muscle originates from the sternum or intraclavicular region and is inserted into the rectus sheath, costal cartilage, lower ribs, and external oblique aponeurosis. It innervated by the anterior thoracic or intercostal nerves. Conclusion: The sternalis muscle is a relatively unusual anatomic variation in plastic surgery. However, by sharing the case for this muscle and considering the versatility of this muscle, it is possible not only to prevent surgeon from being confused and going wrong dissection plane during the surgery, but also to be applicable to several reconstructive procedures including covering the medial side of an implant or expander in breast reconstruction surgery.

Biography :

Seong Yeon Kim has completed her MD from Ewha School of Medicine, Ewha Womans University and trained as Resident in Department of Plastic and Reconstructive Surgery, college of medicine, the Catholic University of Korea. Now she is in Fellowship in Bucheon St. Mary’s Hospital, College of Medicine, The Catholic University of Korea.

E-mail: yiaddung@gmail.com

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