To all who enjoy trivia--

The development of the breast begins in the embryo as a band of ectodermal
tissue which folds inward, beginning about the 5-6th week post-conception.
This fold forms a band of tissue which extends from the axilla to the groin.
This band is first called the galactic band, milk streak, or milk line at
35-37 days post-conception.  As the fold rises, it is called the mammary
crest or mammary hillock (40-42 days).  As point(s) along the band begin to
develop mammary tissue, these points are called mammary buds (49 days).
Usually only one spot along the band develops into mammary tissue, but it is
not uncommon to see errant development.

The ingrowing ectodermal mass divides and branches and a lumen forms within
each branch by about 32 weeks gestation.  Near term, 15-25 mammary ducts
form the fetal mammary gland which is capable of responding to hormonal
stimulation.

The mesoderm gives rise to the connective tissue framework of the breast as
well as the essential fat pad.  Maldevelopment or trauma to the mammary
tissue during fetal development can seriously compromise the development of
the mature gland.

Terms:
        hypermastia - presence of accessory mammary glands
        hyperthelia - excess nipple tissue without corresponding breast
tissue           hyperadenia - mammary tissue without nipple

Cindy Smith
[I knew all those embryology courses would pay off someday!]
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Cindy Smith
Editor, Breastfeeding Abstract
LLLI Board of Directors
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