Blood Supply of the Breast and Thoracic Wall

Blood Supply of the Breast and Thoracic Wall. The breast receives its blood supply from (1) perforating branches of the internal mammary artery; (2) lateral branches of the posterior intercostal arteries; and (3) several branches from the axillary artery, including highest thoracic, lateral thoracic, lateral thoracic, and pectoral branches of the thoracoacromial artery. (figure 2-6)

Blood Supply of the Breast

The lateral thoraic artery gives branches to the serratus anterior muscle, both pectoralis muscles, and the subscapularis muscle. The lateral thoracic artery also gives rise to lateral mammary branches that wrap around the lateral border of the pectoralis major muscle to reach the breast.

The intercostal arteries originate in two groups: the anterior and the posterior intercostal arteries. The anterior intercostals are usually small paired arteries that extend laterally to the region of the costochondral junction. The anterior intercostal arteries of the upper five intercostal spaces arise from the musculophrenic artery. The posterior intercostals for the first two spaces arise from the superior intercostal artery. The posterior intercostal arteries, except for the first two spaces, arise from the thoracic aorta. The posterior intercostals for the first two spaces arise from the superior intercostal artery, which is a branch of the costocervical trunk.

The thoracodorsa branch of the subscapular artery is not involved in the supply of blodd to the breast, but it is important to the surgeon  who must deal with this artery during the dissection of the axilla. The central and scapular lymph node groups are intimately associated with this vessel.

A fundamental knowledge of the pattern of venous drainage is important because carcinoma of the breast may metastasize through the veins and because lymphatic vessels often follow the course of the blood vessels. The veins of the breast basically follow the path of the arteries, with the chief venous drainage toward the axilla. The superficial veins demonstrate extensive anastomoses that may be apparent through the skin overlying the breast. The distribution of these veins has been studied by Massopust and Gardner and Haagensen using photographs taken in infrared light. Around the nipple, the veins form this article, the circulus venosus. Veins from this circle and from the substance of the gland transmit blood to the periphery of the breast and then into vessels joining the internal thoracic, axillary, and internal jugular veins. 

The three groups of deep veins that drain the breast and serve as vascular routes include the following:

1. The intercostal veins, which traverse the posterior aspect of the breast from the second to the sixth intercostal spaces and arborize to enter the vertebral veins posteriorly and the azygos vein centrally to terminate in the superior vena cava.

2. The axillary vein, which may have variable tributaries that provide segmental drainage of the chest wall, pectoral muscles, and the breast.

3. The internal mammary vein perforators, which represent the largest venous plexus to provide drainage of the mammary gland. This venous network traverses the rib interspaces to enter the brachicephalic (innominate) veins. Thus perforators that drain the parenchyma and epithelial components of the breast allow dircet embolization to the pulmonary capillary spaces to establish metastatic disease.

Three principal groups of veins are involved in the venous drainage of the thoracic wall and the breast: (1) perforating branches of the internal thoracic vein, (2) tributaries of the axillary vein, and (3) perforating branches of posterior intercostal veins. Metastatic emboli travelling through any of these venous routes will pass through the venous return to the heart and then be stopped as they reach the capillary bed of the lungs, providing a direct venous route for metastasis of breast carcinoma to the lungs.

The vertebral plexus of veins (Batson's plexux) may provide a second route for metastasis of breast carcinoma via veins. This venous plexus surrounds the vertebrae and extends from the base of the skull to the sacrum. Venous channels exist between this plexus and veins associated with thoracic, abdominal, and pelvic organs. These vessels provide a route for metastatic emboli to reach the skull, vertebrae, ribs, pelvic bobes, and central nervous system.