The right subclavian duct often drains directly into the venous system. Apical nodes also have drainages into cervical and supraclavicular nodes. Metastatic disease in these nodes is especially difficult to remove. The medial aspect of the breast is drained by intercostal vessels into parasternal nodes. Parasternal and paratrachial drainages combine to form the bronchomediastinal lymph trunks.
Drainage continues into the right lymphatic duct on the right and the thoracic duct on the left.
The breast is also drained by subcutaneous vessels. These vessels have a wide distribution ranging from the cervical region to the inguinal region and crossing the midline. If the deeper lymph channels are blocked, as may be the case with cancer, subcutaneous drainage may greatly increase and widely disperse cancerous cells. Most of this drainage is into the pectoral nodes located along pectoral branches of the thoracoacromial vessels. Pectoral nodes drain into the apical nodes located near the apex of the axilla.