An accessory muscle of the thoracic wall

Introduction Customary dissection in the Physical Therapy Anatomy Laboratory yielded a unilateral left-sided pectoral variation in a single cadaver. The cadaver was a 60-yearold Caucasian male. The variant included two separate thoracic wall muscles between the pectoralis major and pectoralis minor muscles. One muscle was identified as a pectoralis quartus and the other as an accessory thoracic wall muscle. Although there are many pectoral variations documented in the literature, to the authors’ knowledge, there are none identical to the current case.