The breast and pectoral region is on the anterior and superior part of the thorax (chest). In addition to containing muscles and fascia that assist in movement of the upper limb, this region also contains the mammary glands, which secrete milk
The axilla is the name given to an area that lies underneath the glenohumeral joint, at the junction of the upper limb and the thorax. It is a passageway by which neurovascular and muscular structures can enter and leave the upper limb.
Anatomy is a branch of natural science which deals with the structural organization of living things. It is an old science, having its beginnings in prehistoric times.