SUMMARY A rare case of two additional slips in the origin of the sternal and clavicular head of the left sternocleidomastoid muscle was found during routine dissection of neck in a 65-year-old male cadaver. One of the additional heads originated in the clavicle and another head shared its origin in both the clavicle and the sternum. Both the additional heads joined with the main heads of the sternocleidomastoid muscle in the middle of the neck. The insertion, nerve supply, and blood supply were normal. The aim of our study was to report a case of variation in the sternal and clavicular origin of the sternocleidomastoid muscle and to provide detailed information about this new variation. This case may be important for head-andneck surgeons for muscle grafting, as well as for radiologists while interpreting MR/CT scans of neck region
