Anatomy of Breast

Breast Anatomy

The word breast is derived from the old English word breost which meant bosom. The breast or mammary gland is found in the pectoral region and is of high importance.

It is present in both sexes but is rudimentary in the male and well developed in the female. Mammary gland is an exocrine gland found in humans and other mammals that produces milk to feed the newborn. It is also one of the accessory organ of female reproductive system The amount of fat in the breast determines its size

Anatomy of breast

The breast lies in the pectoral region in the superficial fascia, they overlie the pectoralis major muscle. When studies a breast is divided into 4 quadrants that are as follow:-

  1. Upper medial quadrant
  2. Lower medial quadrant
  3. Upper lateral quadrant
  4. Lower lateral quadrant

In the upper lateral quadrant a small extension known as axillary tail of spence(spence’s tail, axillary tail) passes through an opening in the deep fascia and lie in the axilla this opening is known as foramen of langer this foramen is known as a defect in the deep pectoralis fascia. The axillary tail has a clinical importance too if enlarged it may be misdiagnosed as a lipoma or axillary lymphadenopathy.

The breast lies on the deep fascia that is also known as pectoral fascia covering the pectoralis major. It is separated from deep fascia by an loose areolar tissue called the retro mammary space it is due to this space that the breast can be moved freely.

Structure of the Breast 

The structure of the Breast is divided into 3 parts:-

  1. The skin
  2. The parenchyma 
  3. The stroma

The skin:- covers the whole gland and has the following two features:-

➥Nipple:- a conical projection present just below the centre of the breast at the level of 4th intercostal space. It is rich in its nerve supply and has circular and longitudinal muscle fibres which make it stiff and also flatten it. It also has lactiferous ducts, 15-20 in number. Few modified sweat and sebaceous glands are also present in the nipple.

➥Areola:- circular pigmented area around the nipple is known as areola.

This area is rich in sebaceous glands especially around the outer margin, during pregnancy the sebaceous glands become enlarged and form raised tubercles called Montgomery tubercles. These sebaceous glands lubricate the nipple and areola preventing them from cracking during lactation.

The parenchyma:- it is made up of glandular tissue which secretes milk. Each gland has  15-20 lobes, every lobe has a cluster of alveoli drained by a lactiferous duct.

The stroma:- it forms the supporting framework of the gland. It is partly fatty forms the main bulk of the gland and partly fibrous forming the septa, also known as ligaments of cooper which anchor the skin and gland to the pectoral fascia.

Blood supply/ Nerve supply/ Lymphatic drainage of the breast

➥Blood supply Internal thoracic artery branch of subclavian artery.
Lateral thoracic,superior thoracic and acromiothoracic artery branches of axillary artery.
Lateral branches of posterior intercostal arteries.
➥Venous drainage The superficial veins drain into the internal thoracic vein.
The deep veins drain into the internal thoracic, axillary and posterior intercostal veins.
➥Nerve supply Anterior and lateral branches of the 4th, 5th, 6th intercostal nerves.
➥Lymphatic drainage Axillary nodes 75% drainage.
Internal mammary nodes 20% drainage.
Posterior intercostal nodes 5% drainage.

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