Mammary Gland Flashcards
What are the characteristics of the mammary gland?
It is a modified sweat gland
Accessory female reproductive organ
What is the vertical extent of the mammary gland?
2nd to 6th rib in mid clavicular line
What is the lateral extent of the mammary gland?
Lateral border of sternum to mid-axillary line along the 4th rib
What is the mammary bed?
Base on which the gland rests formed by:
* Pectoralis major-medial 2/3rd
* Serratus anterior-lateral 1/3rd
* External oblique aponeurosis in infero-medial quadrant
What is the retromammary space?
Loose connective tissue between the base of gland and the deep fascia covering mammary bed
What is the axillary tail of Spence?
Tail-like projection enters the axilla
What is the nipple?
Conical projection at the level of 4th intercostal space
What is the structure of the nipple?
- Pierced by 15-20 lactiferous ducts
- Circularly & longitudinally disposed smooth muscles
- Rice nerve supply
- No subcutaneous fat or hair
What is the areola?
Pigmented circular area around the base of the nipple
What is the structure of the areola?
Modified sebaceous glands on the outer margin-tubercles of Montgomery-lubrication
Beneath the areola lactiferous ducts dilate to form lactiferous sinus before passing through the nipple
Lymphatic plexus of sappy- subareolar
Define parenchyma
Parenchyma is the functional tissue of an organ as distinguished from the connective and supporting tissue.
What are lobes in the parenchyma?
A lobe is a cluster of alveoli drained by a lactiferous duct (milk ducts, mammary ducts)
Describe the lobes
Composed of glandular tissue compound: tubulo-alveolar arranged in lobes
15-20 pyramidal lobes
Lobes are arranged in radiating manner converge towards the areola
What is the lactiferous sinus?
Slight dilatation of lactiferous duct beneath the areola.
Small amount of milk may accumulate here in active gland
What are myoepithelial cells?
Found around the alveoli and ducts.
Their contraction facilitate passage of the milk from the alveoli
What are the support structures of the breast tissue?
Stroma: Supporting framework of the gland
Ligaments of Cooper: Bands of fibrous, flexible connective tissue underlying the pectoral fascia
Fatty tissue
Describe mammary glands in prepuberty
Presence of lactiferous ducts without alveoli
Describe mammary glands at puberty
Ducts undergo branching
Forms solid masses which are precursors of alveoli
Describe mammary glands during pregnancy and lactation
Proliferation & epithelial growth of ducts & lobules
Increase in the number of alveoli
Which arteries supply the mammary glands?
Internal thoracic artery: Perforating branches
Axillary artery: Lateral thoracic, superior thoracic & thoraco-acromial branches
Posterior intercostal arteries: Lateral branches
Which veins drain the mammary glands?
Veins follow the arteries and form the plexus circulous venosus under the areola
Superficial veins drain into internal thoracic vein
Deep veins drain into internal thoracic, axillary & posterior intercostal veins
Describe the nerve supply of the mammary glands
Supplied by anterior and lateral cutaneous branches of 4th to 6th intercostal nerves
Convey sensory fibers to the skin
Autonomic fibers to smooth muscles
Note: These nerves do not control milk secretion. It is controlled by hormone prolactin
Describe the deep lymphatic drainage of the mammary glands
Deep lymphatics: Drain the parenchyma including areola & nipple
75% drained by axillary lymph nodes – end mostly in anterior group close to the axillary tail of spence partly into posterior & apical groups
20% drained into parasternal group from both medial & lateral parts
5% drained into posterior intercostal nodes
Describe the superficial lymphatic drainage of the mammary glands
Superficial lymphatics: Drain the overlying skin excluding areola & nipple
Outerpart: axillary nodes
Upper part: supraclavicular nodes
Inner part: parasternal nodes
