(474.41) An Accessory Muscle of the Pectoral Region

Poster Board Number: C41
Introduction: AAA has separate poster presentation times for odd and even posters.
Odd poster #s – 10:15 am – 11:15 am
Even poster #s – 11:15 am – 12:15 pm

Harrison Moses (Oakland University William Beaumont School of Medicine), Melanie Ermler (Oakland University William Beaumont School of Medicine), Brandon Phan (Oakland University William Beaumont School of Medicine), Cloe Nazeer (Oakland University William Beaumont School of Medicine), Anne Heukwa (Oakland University William Beaumont School of Medicine), Malli Barremkala (Oakland University William Beaumont School of Medicine)

Among the variations of pectoral muscles, this case is unique in the literature. An accessory pectoral muscle located deep to the left pectoralis minor, and attached to ribs 4-6 near the midclavicular line, was discovered during a routine anatomy dissection. The muscle fibers do not fuse with fibers from other muscles, yet they run parallel to pectoralis minor. The accessory muscle can be distinguished from pectoralis minor because it has its own investing fascia and because subcutaneous fascia lies posterolaterally to the accessory muscle. These features place it in a distinct plane with unique innervation. This muscle holds clinical importance in that it may be a consideration for surgeons performing procedures including pectoral flap surgeries. Further, breast imaging may be complicated by such unexpected variations in the muscle tissue.