For adequate treatment of patients with breast cancer, mastologists should have a complete understanding of the anatomy of the thoracic wall, axilla and breast. However, the classical anatomical descriptions in textbooks make it difficult to gain full mastery of this subject, because the books usually deal with its elements separately. In an endeavor to resolve this difficulty, the present authors have conducted an extensive review, to describe the muscles, blood vessels and nerves of the thoracic wall and in the axilla that are of interest to mastologists. The axilla was described in detail, with emphasis on its limits, walls and contents, and highlighting the lymph nodes in this region. Finally, the anatomy of the breast and its topography, innervation, vascularization and lymph drainage were described, making correlations between the anatomy and the lymph node group classification routinely used by mastologists