Final answer:
The sternal, axillary, and mammary regions are all part of the chest region, referring to the upper part of the anterior surface of the body.
Step-by-step explanation:
The sternal, axillary, and mammary regions are all parts of the chest region. The sternum is a long, flat bone in the center of the chest that anchors the anterior thoracic cage, consisting of the manubrium, body, and xiphoid process. The axillary region refers to the armpit area, while the mammary region pertains to the breast area. These areas collectively refer to the upper part of the body's anterior (ventral) surface and are all located above the abdominals and form part of the thoracic area, which includes the rib cage protecting vital organs such as the heart and lungs.