Anatomy of the Breast
Definition
Breasts or mammary glands are accessory glands of the female reproductive system
Present in the male in a rudimentary form.
Small until puberty
After puberty the breast grows to its mature size at pregnancy
It is under the influence of the hormones oestrogen and progesterone
After parturition – prolactin ® milk production oxytocin ® release of milk in response to stimulation of the nipples by the sucking of the baby
Structure
Glandular tissue – secretion of milk
Fibrous tissue – supports the glandular tissue
Fatty tissue – covers the surface and fills the gap between the lobes and gives a smooth contour to the breast - about 20 lobes of glandular tissue
lobes consist of lobules
lobules consist of clusters of alveoli – glandular epithelium - milk secretion - flows into small ducts called lactiferous ducts – lactiferous converge towards the centre of the breast
At the centre dilatations or reservoirs for milk
From each dilatation or lactiferous sinus a narrow duct passes on to the surface of the nipple.
The nipple
Conical eminence at the centre of the breast
Surrounded by a pigmented area called the areola
On the surface of the areola numerous sebaceous glands (Montgomery’s tubercles). They lubricate the nipple during lactation.
Blood supply
Arterial supply
Thoracic branches of the axillary arteries
Internal mammary artery
Intercostal arteries
Venous drainage
Anastomotic circle round the base of the nipple – branches – to the circumference – end in the axillary and mammary veins
Lymph drainage
Axillary lymph nodes
Internal mamary nodes
Nerve supply
Branches from the 4th, 5th and 6th thoracic nerves – sympathetic - there are numerous somatic sensory nerve endings in the breast especially around the nipple . – touch receptors – sucking – stimulated – impulses to hypothalamus – oxytocin – release of milk
Applied anatomy
The main lymphatic drainage is by axillary group of lymph nodes. So in operations for cancer breast "axillary clearance" is a must removing the axillary lymph nodes.
