The Female breast :

The female breast overlies the second to the sixth rib;two third of it rests on pectoralis major, one-third on serratus anterior, while its lower medial edge just overlaps the upper part of the rectus sheath.

Structure:

The breast is made up of 15-20 lobules of glandular tissue embedded in fat . the fat part account for its smooth contour and of its bulk. The lobules are are separated by fibrous septa running from the subcutaneous tissues to the fascia of the chest wall ( the ligaments of Cooper)

Each lobule drains by its lactiferous duct on to the nipple, which is surrounded by the pigmented areola . this area is lubricated by large modified sebaceous glands called gland of Montagomery.

The blood supply :

1.    from the axillary artery via its lateral thoracic and the acromio-throracic branches.

2.   from the internal thoracic (internal mammary)artery via its perforating branches ; these pierce the first to the fourth intercostal spaces ,then transverse pectoralis major to reach the breast along its medial adge.

3.   from the intercostal arteries via their lateral perforating branches;a relatively unimportant source.

The lymphatic drainage :

About three quarters of the lymphatic drainage is to the axillary nodes:

(1) Lymphatics pass around the edge of the pectoralis major and reach the pectoral group of axillary nodes;

(2) routes through or between the pectoral muscles may lead directly to the apical nodes of the axilla;

(3) lymphatics follow the blood vessels through the pectoralis major and enter the parasternal (internal thoracic) nodes;

(4) connections may lead across the median plane and hence to the contralateral breast;

(5) lymphatics may reach the sheath of the rectus abdominis and the subperitoneal and subhepatic plexuses.

It should be noted that free communication exists between nodes below and above the clavicle and between the axillary and cervical nodes.