PATHOLOGY

Detailed explanation-1: -There are two such muscles on each side of the sternum (breastbone) in the human body: pectoralis major and pectoralis minor. The pectoralis major, the larger and more superficial, originates at the clavicle (collarbone), the sternum, the ribs, and a tendinous extension of the external oblique abdominal muscle.

Detailed explanation-2: -The pectoralis major is the superior most and largest muscle of the anterior chest wall. It is a thick, fan-shaped muscle that lies underneath the breast tissue and forms the anterior wall of the axilla.