Breast

The breast or mammary gland is an important structure of the pectoral region. It is present in both sexes. It develops into an important organ of female reproductive system after puberty, while it remains as a rudimentary structure in males.

Embryology

Breast is a modified sweat gland derived from the ectoderm.

Anatomy

Situation

Breast is situated in the pectoral region and the protuberant part extends vertically from the second to the sixth ribs in the mid-clavicular line and horizontally from the lateral border of sternum to the mid-axillary line. In fact, a thin layer of breast tissue overhangs these boundaries extending from the clavicle to the eighth rib and from midline to the edge of latissimus dorsi muscle. This needs to be considered in mastectomy operations requiring removal of the entire breast. The major part of the breast lies over the pectoralis major muscle and the rest upon the serratus anterior and external oblique muscles.

Structure

Skin

The structural elements of breast include the skin, parenchyma and the stroma. The skin of the breast forms a covering for the underlying glandular and fatty tissue. The nipple is usually present below the centre of the breast overlying the fourth intercostal space. It is covered by thick skin with corrugations. It contains smooth muscle fibres arranged concentrically and longitudinally, which make the nipple erect or less prominent respectively. At the apex of the nipple lie the openings of the 15-20 lactiferous ducts which are channels connecting the milk secreting alveoli and the nipple through the intermediary ductules. Each of these lactiferous ducts has a terminal ampulla which acts as a temporary reservoir for milk in lactating women.
The base of the nipple is pigmented and forms the areola. The epithelium of the areola contains numerous sweat and sebaceous glands which rise during pregnancy and lactation and are called the Montgomery’s tubercles. The oily secretions from these glands serve to lubricate the nipple and areola during lactation. The areola and nipple are devoid of hair and subjacent fat.

Parenchyma



about                    contact us              disclaimer             faqs                    privacy           LifeHugger © 2008-2017