Introduction: the breast is an accessory organ of reproduction. It produces milk for the growing baby. It is rudimentary in the prepubertal female and males. It consists of glandular tissues, ducts and supporting tissues.
Shape: conical in shape. It has a base and an apex.
Base: the base of the breast lies on the superficial fascia. It extends from T2 to T6 in the midclavicalar line in the vertical plane and from the midaxillary line in the axillary to the sternum in the horizontal plane. The base overlies the pectoralis  major muscle medially and anteriorly, the serratus  anterior anterolaterally and the external oblique muscle inferiorly.
Apex: the apex of the breast is the nipple which is made up of longitudinal and circular muscles. The base of the nipple is the areola which contains no fat but rich in sebaceous and sweat glands.
Structure: the breast consists mostly of fibrous and fatty tissues. Variation in size is due to variation in fat content. Fibrous septae divide the breast into irregular lobules from which lactiferous duct converge to open on the tip of the nipple.
Blood supply: this is mainly from the lateral thoracic artery. The internal thoracic artery also sends branches through the intercostal spaces. The thoracoacromian artery supplies the upper part of the breast.
Venous drainage: is by deep veins to internal thoracic and axillary veins.
Nerve supply: the overlying skin is supplied by the cutaneous branches of intercostal nerves T4 to T6. Sympathetic fibres supply blood vessels and glands
Lymph drainage: lymph drains mainly to the axillary lymph nodes and also to the internal thoracic (parasternal) lymph nodes.
Clinical correlates:
1. Cancerous cells are carried from the breast by lymph vessels to lymph nodes, chiefly those in the axilla. The cells lodge in these nodes where they produce nests of tumors cells called metastasis.
2. Cancerous cells can Cross the midline to the other breast due to free communication between them.