INTRODUCTION AND DEVELOPEMENT OF BREAST

The human breast reaches its full functional capacity
during lactation with the production of breast milk. In
order to diagnose and treat breastfeeding problems and
pathologies that arise during lactation, it is essential to
have an extensive understanding of the normal anatomy
and physiology of the breast. This review details the
development of the breast and the most recent findings in
breast anatomy. The effect breast anatomy has upon
clinical practice as well as the importance of milk
ejection is reviewed.
DEVELOPMENT OF THE BREAST
While it is undisputed that breast milk provides the
optimal nutrition for the developing infant, breast milk
also contains unique protective factors for the mother.
1
It
has been hypothesized that the mammary gland first
evolved from the innate immune system as an inflamma-
tory response to provide protection to the young, and that
nutritional factors developed later.
2,3
To date, nutrition
has assumed a position of dominance over the protective
factors in considerations of the physiology of human
lactation.
The human breast is a dynamic organ that does not go
through all developmental stages unless a woman expe-
riences pregnancy and childbirth. The course of breast
development can be described in distinct phases begin-
ning with the fetal phase and progressing through the
neonatal/prepubertal and postpubertal phases. Develop-
ment of the breast can then proceed through a number of
lactation cycles (pregnancy, lactogenesis I, lactogenesis
II, and involution