Unilateral Sternalis With Double Slips: An Astounding Muscle, Often Unnoticed and Unknown.

Discovery and variations of rectus sternalis muscle are occasionally seen in humans. However, during routine academic dissection of an adult male embalmed cadaver, a rare variant of the muscle was identified. The muscle had origin from the pectoral muscle and fascia and was inserted into external oblique aponeurosis along with the sixth rib and cartilage. It had double slips with the partial merging of the bellies. Knowledge regarding such unique muscle is important to anatomists for medical education as well as to surgeons during thoracic surgeries, in craniocaudal mammography where it can mimic breast mass and for using as muscle flap in the anterior chest wall, head and neck, and breast reconstructions.