THE HUMAN BREAST

THE HUMAN BREAST

The human breast is normal and standard equipment among women, and mammary glands are common among mammals. That is why they are referred to as mammae, and children refer to their mothers as "mamma". A child knows its mamma from others and distinguishes her from their father because "she" is the one with the breasts.

The breast is made up of both fatty tissue and glandular milk-producing tissues. The ratio of fatty versus glandular tissue varies among individuals. In addition, with the onset of menopause (ie, decrease in estrogen levels), the relative amount of fatty tissue increases as the glandular tissue diminishes. The soft tissues of the breast are supported by the suspensory ligaments of Cooper. These ligaments run throughout the breast tissue parenchyma from the deep fascia beneath the breast and attach to the dermis of the skin. Since they are not taut, they allow for the natural motion of the breast. Eventually, this results in breast ptosis since these ligaments relax with age and time. Sensory innervation of the breast is dermatomal in nature. It is mainly derived from the anterolateral and anteromedial branches of thoracic intercostal nerves T3-T5. Supraclavicular nerves from the lower fibers of the cervical plexus also provide innervation to the upper and lateral portions of the breast. Researchers believe sensation to the nipple derives from the lateral cutaneous branch of T4. The blood of the breast skin depends on the subdermal plexus, which is in communication with underlying deeper vessels supplying the breast parenchyma. The blood supply is derived from (1) perforating branches of the internal mammary artery, (2) the lateral thoracic artery, (3) the thoracodorsal artery, (4) intercostal artery perforators, and (5) the thoracoacromial artery. This rich blood supply allows for growth, development, repair as in modeling after pregnancy and lactation. The breast lies over the musculature that encases the chest wall. The muscles involved include the pectoralis major, serratus anterior, external oblique, and rectus abdominus fascia. The blood supply that provides circulation to these muscles then perforates through to the breast parenchyma, thus also supplying blood to the breast. By maintaining continuity with the underlying musculature, the breast tissue is richly supplied with oxygen, hormones and nutritionly enriched blood.