The breast receives its blood supply from the following arteries:

1. Lateral thoracic
   
   
2. Perforating branch of internal thoracic
   
   
3. Perforating branch of posterior intercostal arteries
   
   
4. Twigs from superior thoracic and pectoral branch of tharacoacromial.

Veins correspond and end in the axillary vein, or subclavian vein directly.

Veins which accompany the intercostal veins, end in the azygous venous system.

The intercostal veins communicate with the external and from thence to the internal vertebral venous plexus.

There are two plexuses of lymphatic vessels i.e. the subareoalar and the perilobular. These anastomoses freely. Their efferents are shown.

1. 78-80% to the axillary lymph nodes
   
   
2. 20% to the parasternal nodes

Communicate with:

• Opposite breast
  
  
• Infraclavicular and supraclavicular nodes
  
  
• Subperitoneal and subdiaphragmatic nodes 

What is the importance of the lymphatic drainage in breast cancer metastasis?