anatomy and physiology and development of normal breast with applied aspects

1. BREAST
S.Sanjay
FINAL YEAR MBBS

2. ANATOMY
• Breast is a modified sweat gland derived
from ectoderm, as branching epithelial
cords which form lactiferous ducts.
• It lies within the superficial fascia(sub-
cutaneous).
• It is present in both the sexes.
• Rudimentary in male and well developed
in female after puberty.
• EXTENT
• Vertical - 2nd to 6th ribs.
• Horizontal - Lateral border of sternum
to anterior axillary line.
• 2/3rd of breast rests upon pectoralis
major.
• 1/3rd rests upon serratus anterior.

3. AXILLARY TAIL OF SPENCE
 It is the prolongation of
Superolateral quadrant to the
axilla along the lower border of
pectoralis major through an
opening in the deep fascia called
Foramen of Langer.
 It is sometimes mistaken for an
enlarged lymph node or a
lipoma.

4. STRUCTURES DEEP TO BREAST
 Retromammary space
 Pectoral deep fascia
 Pectoralis major
 Serratus anterior
 External oblique
 Chest wall

5.  AREOLA
 A circular pigmented area around the
nipple.
 It contains involuntary muscle, sweat
glands and sebaceous glands which
enlarges during pregnancy and helps in
lubrication during lactation
(Montgomery tubercles).
 NIPPLE
 It is located at the level of 4th intercostal
space.
 Covered by thick skin with corrugations.
 Near its apex lie the orifices of the
lactiferous ducts.
 Erectile structure – smooth muscle
fibres arranged concentrically and
longitudinally- resemble panniculus
carnosus.

6. SUSPENSORY LIGAMENT OF
COOPER
They are hollow conical projections of
fibrous tissue.
Anchors breast to underlying superficial
pectoral fascia and to the overlying skin .
These ligaments account for the dimpling of
the skin overlying a carcinoma.

7. LOBES
 15 to 20 in number.
 Composed of glandular structures called
lobules which empty via ductules into
lactiferous duct.
LACTIFEROUS DUCTS
 It drains each lobes of the breast pass through
the nipple and open on its tip as 15 to 20
orifices.
 Contains ampulla near its end (Reservoir for
milk or abnormal discharge)

8. Histology of ducts and acini

9. Cont…

10. Histology of breast
 Lined by a layer of cuboidal
epithelium(single layer thick in smaller
ducts, two cells thick in the larger ducts)
 They lie on the myo-epithelial
cells(ectoderm) and basement
membrane.
 The morphology varies with age,
menstrual cycle, pregnancy and
lactation.
 Close to the opening of lactiferous duct
they become from columnar to
keratinizing stratified squamous

11. Embryology of breast

12. Cont…
5-6th
week, two
ventral
bands of
epithelium
forms from
axilla to
groin
region(Mil
k line of
schlutz)
At day
49,
thoracic
bud only
invaginat
es and
rest
vanish
The
ectoderm
ingrowth
forms
lactiferous
duct and
acini,
surrounding
perisomatop
leuric
mesoderm
forms the fat
and fascia.
At day
56, the
nipple
forms
At day
84,
Primitive
mammar
y sprouts
At 15th day,
canalization
occurs
The ducts
open into
the
mammary
pits

13. Applied:
 Witch’s milk :
◦ Milk secreted from the new born infants.
◦ Due to combination of fetal prolactin and
maternal oestrogens
 Polythelia
◦ Presence of extra nipples in the body.
◦ They’ll usually develop along the milk line.
 Athelia :
◦ Absence of nipple devolpement.

14. BLOOD SUPPLY OF BREAST
 Internal thoracic artery- 60%
 Perforating cutaneous branches to
2nd 3rd and 4th intercostal spaces
 Axillary artery- 30%
 lateral thoracic artery (2nd branch)
 pectoral branch of acromiothoracic
artery
 superior thoracic artery
 Lateral branch of 2nd 3rd and 4th
intercostal arteries.

15. VENOUS DRAINAGE OF BREAST
 Initially they converge around the nipple to form a
circular venous plexus.
 SUPERFICIAL VEINS – drain into axillary, internal
mammary and intercostal vessels.
 Through posterior intercostal veins they communicate
with paravertebral venous plexus (Batson’s plexus) - CA
Breast metastasis to vertebrae.

16. NERVE SUPPLY OF BREAST
 Anterior and lateral cutaneous branches of 4th to
6th intercostal nerves.

17. LYMPHATIC DRAINAGE OF BREAST
AXILLARY LYMPH NODES – 75%
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.
Interpectoral - also called Rotter’s node lies between the
pectoralis major and minor muscles.
Apical - also called subclavicular or Halsted nodes.
lies most superior and deep to pectoralis minor medial to
axillary vessels.

19. BERG’S LEVEL OF AXILLARY LYMPH
NODE
 LEVEL I - Below and lateral to
pectoralis minor.
Anterior, posterior and lateral
 LEVEL II - Behind the pectoralis
minor.
Central and interpectoral
 LEVEL III - Above and medial to
pectoralis minor.
Apical

20.  25% drains mainly from medial half of the breast into 2nd
3rd 4th intercostal space internal mammary lymph nodes.
1 to 2 cm lateral to sternal margin.
 Drainage into contralateral axilla and opposite lymph
nodes.
 Sentinel lymph node – first node in the regional
lymphatic basin that receives the lymph flow from the
primary tumor.

21. PHYSIOLOGY OF LACTATION
 Mammogenesis - Development of breast to a
functional state.
 Lactogenesis - Synthesis and secretion of milk
from the alveoli.
 Galactokinesis - Ejection of milk outside the
breast.
 Galactopoiesis - Maintenance of lactation.
 Involution- Regression and atrophy post
lactation

22.  Estrogen stimulates growth of the ductal system.
 Progesterone is required for full development of lobe –
alveolar system.
 Prolactin promotes lactation.
 Milk ejection reflex:

23. KEY POINTS
 Breast is derived from ectoderm.
 Extents from 2nd to 6th rib.
 2/3rd rests on pectoralis major and 1/3rd on serratus
anterior.
 Montgomery tubercle is anatomical.
 Axillary tail of Spence extends through foramen of
Langer.
 Infiltration of Cooper’s ligament causes dimpling.
 Internal thoracic artery – 60%
 Batson’s plexus – Metastasis to vertebrae.
 Rotter’s node – Interpectoral node.
 Halsted nodes – Apical lymph node

24. THANK YOU