Résumé
There are two main lymphatic drainage routes of the breast: a superficial system and a deep system, and only the deep one can drain into the internal mammary lymph node (IMLN) which receive about 25%of the lymph of the breast. As one of the important nodal sites of lymphatic spread of breast, IMLN is important for neoplasm staging and it will guide adjuvant radiotherapy. However, there still lack an effective and feasible minimally invasive diagnosis technology of IMLN, leading to inaccurate staging and over/under-treatment. The“modified injection technique” broke through the bottle-neck of the low internal mammary visualization rate with traditional injection technique, and made the internal mammary sentinel lymph node biopsy possible to be a min-imally invasive assessment for IMLN status, and further guided internal mammary radiotherapy (IM-RT). Patients with IMLN positive should accept IM-RT, with IMLN negative can avoid IM-RT. With the unceasing progress in studies on internal mammary lymph drainage area, patients may obtain the individualized diagnosis and treat-ment. The review summarizes current knowledge on the anatomy and physiology of the lymphatic system of the breast to translate this into implications for clinical practice of IM-SLNB.