Mammary Gland Flashcards
(16 cards)
HORMONES ACTING ON THE GLANDULAR TISSUE:
OESTROGEN – Stimulates the growth and branching of the ducts
PROGESTERONE – Stimulates the alveolar formation at the ends of the branching ducts
OESTROGEN AND PROGESTERONE (PLACENTAL):-
For the formation of true secretary alveoli during pregnancy PROLACTIN AND GROWTH HORMONE: - maintain lactation OXYTOCIN:– Helps milk ejection, initiated by suckling reflex
Arterial supply:
- Perforating branches from the internal thoracic artery of 2nd , 3rd and 4th intercostal spaces
- 2nd perforating artery is usually the largest, and supplies the upper region of the breast, and the nipple, areola and adjacent breast tissue.
- Lateral thoracic, superior thoracic and thoracoacromial branches of axillary artery
- Lateral branches of posterior intercostal artery
Venous drainage:
The veins follow the arteries
* First they converge towards the base of the nipple where they form an anastomotic venous circle
From the anastomotic circle they run into superficial and deep sets
* Superficial veins drain into internal thoracic vein
* Deep veins drain into internal thoracic, axillary and posterior intercostal veins
The metastasis of the breast cancer to the brain occurs through:
Cancer cells of the breast → posterior intercostal vein → vertebral venous plexus → intracranial dural venous sinuses → brain
Nerve supply:
- The nerve supply is primarily somatosensory
- Derived from 2nd to 6th intercostal nerves through their anterior and lateral cutaneous branches
- They provide sensory innervations to the skin and carry autonomic fibres to the smooth muscles and blood vessels of the breast
- The sensory nerves to the areola and nipple play an important role in stimulating the release of milk from the breast in response to suckling by the infant
- The secretion of milk is controlled by the prolactin hormone secreted by the pituitary gland
Lymphatic drainage of the Gland
the Axillary and internal mammary lymph nodes.
arranged in the following groups:
* Lateral, along the axillary vein
* Anterior, along the lateral thoracic vessels * Posterior, along the subscapular vessels
* Central, embedded in fat in the centre of the axilla
THE SENTINEL NODE is defined as the first lymph node draining the tumour-bearing area of the breast.
apical nodes are also in continuity with the supraclavicular nodes and drain into the subclavian lymph trunk
Lymphatics draining the breast are divided into two groups:
Superficial lymphatics – drain the skin of the breast except nipple and areola
Deep lymphatics – drain the parenchyma of the breast and the skin of the nipple and areola
* Plexus of lymph vessels deep to the areola is called subareolar plexus of Sappey
* Lymphatics from the subareolar plexus and most of the lymph from the breast drain into anterior group of axillary lymph nodes
-The lymph from the upper and lower lateral quadrant of breast drain mainly into anterior axillary or pectoral group of lymph nodes, which are situated deep to lower border of pectoralis minor
-The lymph vessels from the deep surface of the breast pierce the pectoralis major and clavipectoral fascia to drain into apical group of lymph nodes
Mammary gland abnormalities:
Polythelia
presence of accessory nipples due to the persistence of the mammary line
Accessory nipple may develop anywhere along the mammary line, but usually appears in the axillary region
Mammary gland abnormalities: Inverted nipple
is a condition in which the lactiferous ducts open into the original epithelial pit that has failed to evert
Mammary gland abnormalities: Polymastia
when a remnant of the mammary line develops into a complete breast
Mammary gland abnormalities: Athelia
Absence of Nipples
Mammary gland abnormalities: Amastia
Absence of Breasts
* These rare congenital anomalies may occur bilaterally or unilaterally.
* They result from failure of development or disappearance of the mammary crests.
* These conditions may also result from failure of mammary buds to form.
Congenital abnormalities: Amazia
- Congenital absence of the breast may occur on one or both sides. It is sometimes associated with absence of the sternal portion of the pectoralis major (Poland’s syndrome).
- It is more common in males.
Congenital abnormalities: Polymazia
- Accessory breasts have been recorded in the axilla (the most frequent site), groin, buttock and thigh.
- They have been known to function during lactation.
Clinical of Breast cancer :
Although any portion of the breast, including the axillary tail, may be involved, breast cancer is found most frequently in the upper outer quadrant. Most breast cancers will present as a hard lump, which may be associated with in drawing of the nipple.
-As the disease advances locally there may be skin involvement with peau d’orange or frank ulceration and fixation to the chest wall.
The spread of breast cancer: Lymphatic metastasis:
-Lymphatic metastasis occurs primarily to the axillary and the internal mammary lymph nodes.
-Tumours in the posterior one third of the breast are more likely to drain to the internal mammary nodes.
What is Peau d’orange :
Peau d’orange is caused by cutaneous lymphatic oedema, where the infiltrated skin is tethered by the sweat ducts, which cannot swell, leading to appearance like an orange skin.
