Sternoclavicularis - A variant of Pectoralis Major Muscle

A rare muscle sternoclavicularis was found in a large triangular gap between the sternocostal and clavicularheads of Pectoralis Major muscle on the right side during routine cadaveric dissection. Sternoclavicularis was seen toarise from the anterior surface of manubrium sterni and the capsule of sternoclavicular joint and was inserted on theanterior surface of middle one third of the clavicle. It was supplied by the lateral pectoral nerve. Sternoclavicularis musclemay help in stabilizing the clavicle and may partially fill the triangular deficit in the origin of the Pectoralis Major. Thisvariation may be of particular interest to plastic surgeons, orthopaedic surgeons, radiologists and neurologists. It maymimic a tumour at this site.