Quick Review: Breast Cancer

Abstract

The breast is centered over the pectoralis major muscle. Its borders are the clavicle; sternum, 6th and 7th rib inferiorly, and is laterally bounded by the pectoralis and serrratus anterior muscles. The innervation of the breast is derived from the anterior branches of the intercostal nerves 2 through 6 with the nipple receiving its innervation from the 4th intercostal nerve. The major blood supply in order of importance is the internal mammary branches, lateral thoracic, thoracodorsal perforating vessels from the pectoral branch of the throacoacrominal branch of the axillary artery and small intercostals branches. Venous and lymphatic drainage parallel the blood supply. The breast tissue is composed of epidermis, dermis, superficial fascia, glandular breast tissue, deep fascial layer and the pectoralis major fascia and muscle. The glandular tissue consists mainly of epithelium, fibrous stroma, and fat. The breast is organized into roughly 20 lobular units made up of terminal ductals surrounded by fat and fibrous tissues and efferent ductules. These terminal ductals coalesce and drain towards the areola forming a single large duct that contributes to the nipple.