The axillary lymph node group does not include the sentinel lymph node and Wikipedia says it is a “hypothetical ” lymph node which is the first to be drained by a tumour. It also has a significant role in diagnosis of breast cancer. [Thieme atlas of anatomy]
1) Is sentinel lymph node actually present? If yes why is it not included in axillary lymph node group?
2)How do they affect metastasise?