Regarding surgical anatomy and of physiology of breast

1. ANATOMY AND PHSIOLOGY
OF BREAST WITH CONGENITAL
ANOMALIES
BY : Dr. P VIJAYENDRA
MODERATOR : Dr. M. VENKATA REDDY,
ASSOCIATE PROFESSOR,
DEPARTMENT OF GENERAL SURGERY.

2. LAYOUT
• INTRODUCTION
• EMBROLOGY
• ANATOMY
• PHYSIOLOGY
• CONGENITAL ANOMALIES
• REFERENCES

3. INTRODUCTION
• The breasts are modified sweat glands.
• The breast lies between the subdermal
layer of adipose tissue and the superficial
pectoral fascia.

4. EMBRYOLOGY
• Embryologically derived from a downward growth
of ectoderm into the underlying mesenchyme.
• The first stage of development occurs at 6 or 8
weeks of gestation, when two strips of thickened
ectoderm, the mammary ridges, grow in a line
extending from the embryonal axilla to the inguinal
region.

6. • Branching epithelial cords appear as 15 to 20
buds, which eventually become lactiferous
ducts and associated alveoli.
• Each cord becomes surrounded by a stroma
of mesenchymally derived fat, connective
tissue, and vascular tissue.

7. • Towards the end of gestation the lactiferous
ducts become canalized and open on to a pit
in the epidermis.
• At the same time, mesenchymal proliferation
beneath the epidermis allows nipple
development

8. ANATOMY
• Breast extends from the 2nd to the 6th rib in
the midclavicular line overlying the pectoralis
major, serratus anterior, and external oblique
muscles.
• Medially, the breasts reach the sternal edge
& laterally the midaxillary line.

9. • The pyramidal axillary tail extends into
the axilla through a defect in axillary
fascia known as foramen of Langer.
• Axillary tail of spence is in direct contact
with main lymph nodes of breast i.e.
anterior axillary nodes.
• A well developed axillary tail is sometimes
mistaken for mass of enlarged lymph
nodes or lipoma.

10. Anatomical extent of breast

11. • As it develops from the skin the breast is
invested with superficial fascia, which divides
into two layers.
• The anterior layer provides a plane of
dissection subcutaneously between the
relatively small, subcutaneous fat lobules and
the larger lobules of mammary fat.

12. • The posterior layer of superficial fascia abuts
the deep fascia derived from the pectoralis
major and serratus anterior, thus producing a
potential space- the retromammary space
• Between the two layers of superficial fascia
there are condensations of fibrous tissue, the
suspensory ligaments of Cooper, which
divide the breast into lobes and act as a
supportive framework.

14. MICROSCOPIC ANATOMY OF
BREAST
• The breast is composed of acini which make
up lobules, aggregation of which form the
lobes of the gland.
• The lobes are arranged in a radiating fashion
like the spoke of a wheel and converge on
the nipple, each lobe is drained by a
lactiferous duct.

15. MICROSCOPIC ANATOMY OF BREAST

16. • The mature breast is composed of three principal
tissue types:
(1) glandular epithelium.
(2) fibrous stroma and supporting structures.
(3) adipose tissue.
• The breast also contains lymphocytes and
macrophages.
• In adolescents, the predominant tissues are
epithelium and stroma.

17. • In postmenopausal women, the glandular
structures involute and are largely
replaced by adipose tissue.
• Cooper’s ligaments provide shape and
structure to the breast as they course from
the overlying skin to the underlying deep
fascia.

18. • Because these ligaments are anchored
into the skin, infiltration of these ligaments
by carcinoma commonly produces
tethering, which can cause dimpling or
subtle deformities on the otherwise
smooth surface of the breast.

19. Arterial supply of breast
• The lateral thoracic artery, from the 2nd part
of the axillary artery.
• The perforating cutaneous branches of
internal mammary artery to the 2nd, 3rd and 4th
intercostal spaces.
• The lateral branch of the 2nd, 3rd and 4th
intercostal arteries.

21. Venous Drainage
• Blood drains from the circular venous
plexus around the areola and from the
glandular tissue of the breast into the
axillary, internal thoracic and intercostal
veins via veins that accompany the
corresponding arteries.

22. Phlebitis of one of these superficial veins
feel like a cord immediately beneath the
skin – ‘Mondors disease’.

23. Lymphatic drainage of Breast
Commonly into the axillary lymph nodes.
1. Anterior group (pectoral) - Main drainage node.
2. Medial group (central) - Next common node.
3. Posterior group (subscapular) - Rare
4. Lateral group – Rare.
5. Interpectoral nodes (Rotter’s nodes) - Signifies the
retrograde spread of tumour. It lies between pectoralis
major and minor
6. Apical

24. Lymphatic drainage of breast

25. • Later they drain into supraclavicular lymph
nodes. 25% drains mainly from medial half of
the breast into 2nd, 3rd, 4th intercostal space
internal mammary lymph nodes.
• Drainage into contralateral axilla and
opposite lymph nodes also occur.
• The concept of Sappey’s subareolar drainage
of lymph centripetally is not well accepted
now.

26. Levels in Axillary Lymph Nodes
Level I : Below the pectoralis minor muscle.
Level II: Behind the pectoralis minor muscle.
Level III: Above the pectoralis minor muscle.

27. Levels of lymph nodes

28. PHYSIOLOGY
• Before puberty, the breast is composed
primarily of dense fibrous stroma and
scattered ducts lined with epithelium.
• Puberty begins between the ages of 9 and 12
years, and menarche begins between 12 to
13 years of age.
• These events are initiated by low-amplitude
pulses of pituitary gonadotropins, which
increase serum estradiol concentrations.

29. • In the breast, this hormone-dependent maturation
(thelarche) entails increased deposition of fat, the
formation of new ducts by branching and
elongation, and the first appearance of lobular
units.
• This process of growth and cell division is under
the control of estrogen, progesterone, adrenal
hormones, pituitary hormones, and the trophic
effects of insulin and thyroid hormone.

30. • The term prepubertal gynecomastia refers
to symmetrical enlargement and projection
of the breast bud in a girl before the
average age of 12 years, unaccompanied
by the other changes of puberty.
• The postpubertal mature or resting breast
contains fat, stroma, lactiferous ducts, and
lobular units.

31. • During phases of the menstrual cycle or in
response to exogenous hormones, the
breast epithelium and lobular stroma
undergo cyclic stimulation.
• The dominant process appears to be
hypertrophy and alteration of morphology
rather than hyperplasia.

32. • In the late luteal (premenstrual) phase,
there is an accumulation of fluid and
intralobular edema.
• This edema can produce pain and breast
engorgement.

33. • With pregnancy, there is diminution of the
fibrous stroma and the formation of new
acini or lobules, termed adenosis of
pregnancy.
• After birth, there is a sudden loss of
placental hormones, which, combined with
continued high levels of prolactin, is the
principal trigger for lactation.

34. • The actual expulsion of milk is under
hormonal control and is caused by
contraction of the myoepithelial cells that
surround the breast ducts and terminal
ductules.

35. • There is no evidence for innervation of these
myoepithelia cells; their contraction appears
to occur in response to the pituitary-derived
peptide oxytocin.
• Stimulation of the nipple appears to be the
physiologic signal for continued pituitary
secretion of prolactin and acute release of
oxytocin.

36. • When breastfeeding ceases, the prolactin
level decreases and there is no stimulus
for release of oxytocin.
• The breast returns to a resting state and to
the cyclic changes induced when
menstruation resumes.

37. Milk ejection reflex
• The sucking stimulation of the breast sends neural
impulses to the hypothalamus.
• The hypothalamus stimulates oxytocin secretion by
paraventricular nuclei cells, and suppresses the release
of prolactin-inhibiting hormone (PIH).
• Oxytocin stimulates myoepithelial cells of secretory
alveoli of the breast, effecting milk passage through the
lactiferous ducts.Prolactin secretion is maintained when
the PIH is suppressed and lactation continues.

39. • Menopause results in involution and a
general decrease in the epithelial
elements of the resting breast.
• These changes include increased fat
deposition, diminished connective tissue,
and the disappearance of lobular units.

40. CONGENITAL ANAMOLIES
• The most frequently observed abnormality seen in
both sexes is an accessory nipple (polythelia).
• Ectopic nipple tissue may be mistaken for a
pigmented nevus, and it may occur at any point
other than milk streak from the axilla to the groin.

41. Rarely, accessory true mammary glands
develop. These are most often located in
the axilla (polymastia)..
• Hypoplasia is the underdevelopment of the
breast;
• congenital absence of a breast is termed
amastia.
• Inversion of nipple:

42. • Congenital retraction of nipple:
– In the development of the breast, there is first
downgrowth of epithelium from the future site
of nipple, forming a pocket or invagination of
the skin.
– Shortly before birth this depression is pushed
up to become an evagination of nipple.
Failure of this process is congenital retraction.

43. • Poland's syndrome-Unilateral hypoplasia
of breast, thorax, and pectoral muscles

44. REFERENCES
• SABISTON 20TH ED.
• LEE MCGREGOR’S SURGICAL
ANATOMY 12TH ED.
• SCHWARTZ 10TH ED.