Surgical Anatomy and physiology of the breast

1. Seminar presentation on;
Surgical anatomy and physiology of the
breast
Presenter: Dr. Ezedin M. (GSR1)
Moderator: Dr. Yoseph (Ass. Professor of surgery)

2. Outline
• Embryology of the breast
• Congenital anomalies
• Anatomy of the breast
• Histology of the breast
• Physiology of the breast
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3. Embryology of the breast
• A modified and specialized Sweat gland formed by diverticula
of epidermis.
• Is of both ectodermal and mesodermal in origin.
• Development starts at 4th week as the mammary ridge.
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4. Cont’d…
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5. Congenital anomalies
• Amastia
• Amazia
• Athelia
• Supernumerary Breasts
– Accessory
– Ectopic
• Polythelia
• Symastia
• Gynecomastia
• Micromastia
• Congenitally inverted nipples
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6. Cont’d…
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7. Cont’d…
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8. Post natal development of breast
Neonatal dev’t
• Radially arranged mammary lobes draining via lactiferous duct
in to ampulla with no alveoli.
• The nipples start to Evert.
• Maternal hormonal effect = witch's milk formation.
• At birth same in both sex.
– Post birth the male breast will remain rudimentary. (Male vs. Female)
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9. Cont’d…
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10. Cont’d…
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11. Anatomy of the breast
• 2nd to the 6th rib in the mid
clavicular line
• Transversely from the lateral
border of the sternum to the
anterior axillary line
• Circular base with diameter of 10
to 12 cm.
• Size depends on different factors.
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12. Cont’d…
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13. Cont’d…
Axillary tail of Spence
• Prolongation of the upper lateral
quadrant toward the axilla.
• Through hiatus of langer in to deep
fascia of axilla.
• Clinical relevance ??
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14. Cont’d…
Fascial system of the breast
• Continuity
– Cervical fascia
– Abdominal wall
• Posterior suspensory ligaments (*)
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15. Cont’d…
Retro mammary bursa
• Between the superficial and deep fasciae is
the retro mammary space.
• Contributes to the mobility of breast.
• a thin layer of loose areolar tissue that
contains lymphatic's and small vessels
• Surgical importance ?
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16. Cont’d…
Ligaments of cooper
– Suspensory ligaments of the breast
– Fuse with overlying superficial fascia just under the dermis and
coalesce as the interlobular fascia in the breast parenchyma joining
with the deep fascia of breast over the pectorals muscle.
– Infiltrated by cancer.
• Horizontal septum
• Ligamentous suspension
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17. Cont’d…
Horizontal septum Ligamentous suspension
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18. Cont’d…
• Skin:
– Nipple
– Areola
– Sebaceous glands
• Parenchyma
– Lobule, ductule
– lobes, ducts
• Stroma
– fat, fibrous tissue
– NVS
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19. Cont’d…
• Cut-away diagram of a mature resting breast.
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20. Nipple areola complex
Nipple
• Thick hairless skin
• Meissener's corpuscle
• Smooth muscle fibers
– (longitudinal vs. circumferential )
Areola
• Color varies with parity and race
• Sebaceous and sweat glands
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21. Breast parenchyma
• It is formed of 15-20 lobes.
• Each lobe is formed of a number of
lobules.
• The lobes and lobules are separated by
interlobar and interlobular fibrous
tissue
• It has from 15-20 lactiferous ducts
which open by the same number of
openings on the summit of the nipple.
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22. Cont’d…
• .
Alveoli
Lobule
Lobe
Lactiferous
duct
Nipple
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23. Breast stromal tissue
• Partly fibrous & partly fatty
• It contains
– Fatty Tissue
– Ligaments
– Blood Vessels
– Lymphatic Vessels
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24. Cont’d….
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Clinical correlate

25. Blood supply
Internal thoracic artery
• Branch of the Subclavian artery
• Supply medial half of the breast
and surrounding skin
• Perforating branches descend
laterally toward the nipple-areolar
complex
• Radial vs. transverse incisions ??
• Inferior part = no major vessles
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26. Cont’d…
Axillary artery
• supplies lateral portion of the
breast.
• Four branches
– Supreme thoracic branch,
– Pectoral branches of the
thoracoacromial artery,
– The lateral thoracic arteries(*)
– Unnamed mammary branches
Posterior intercostal arteries
• lateral branches
• Arteries are distributed in the
anterior surface.
• Posterior surface is relatively
avascular.
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27. Cont’d…
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28. Cont’d…
A segment of the body wall illustrating the relationship
of structures to the ribs.
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29. Venous drainage
Venous drainage follow the arteries.
• First converge around the nipple (Circulus venosus)
• Superficial veins:
– Internal thoracic vein & superficial veins of the lower part of the neck
• Deep veins
– Internal thoracic , Axillary & Posterior intercostal veins
– Batson's vertebral venous plexus
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30. Cont’d…
• Mainly goes through
– Internal thoracic
– Axillary veins
– The intercostal (3rd-5th )
• Connection with batsons plexus.
– Communication with portal vein
• Major venous drainage of the breast has preferential flow toward
the axilla.
• Clinical correlation??
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31. Cont’d…
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32. Lymphatic drainage of the breast
• Superficial lymphatic's :- skin over breast except nipple & areola
• Deep lymphatic's :- parenchyma as well as nipple & areola
– Lymphatic capillaries arise within the interlobular tissue
• Sappey's plexus
• Efferent lymph vessels pass around & lateral edge of Pec minor
and pierce cliavipectoral fascia
– Parasternal internal mammary group (5% vs. 25%)
– Axillary group ( 75%)
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33. Cont’d…
Axillary lymphatic groups
1. Lateral group (axillary vein group)
2. Anterior/pectoral (ext. mammary group) (*)
3. Scapular group ( post/ subscapular group)
4. Central group
5. Interpectoral group (rotter's node)
6. Subclavicular group (*prognosis)
Level I lymph nodes
Level II lymph nodes
Level III lymph nodes
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34. Cont’d…
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Cont’d…

37. Cont’d…
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38. Cont’d…
Clinical coloration
• In breast ca. the other breast and the
opposite axillary lymph nodes are
affected because of the anastomosing
lymphatic's between both breasts.
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39. Breast innervation
• The nervous supply to the breast is primarily by
– Sensory = Nipple and skin
– Sympathetic nerves = Breast parenchyma
• Supply to the surface of the breast.
– The lateral branches of the intercostal nerves (4th to 6th) lateral mammary
branches.
– The anterior branches of the intercostal nerves medial mammary branches;
innervate medial aspect of breast
• Sympathetic fibers
– Anterior or medial branches of the supraclavicular nerve
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40. Cont’d…
Clinical relevance
• Nerves of principal interest to surgeons
– The long thoracic nerve
– The thoracodorsal nerve
– The intercostobrachial nerve (2nd ICN)
– Medial and lateral nerves to the pectoralis major muscle.
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41. Cont’d…
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42. Cont’d…
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43. Structures encountered during mastectomy
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44. Microscopic anatomy of the breast
• It is a modified sweat gland and is said to have an apocrine type
of secretion.
• Duct alveolar system
– Epithelial glandular tissue , the tubulo-alveolar type.
– Composed of dual layers of columnar and cuboidal epithelium
– Myoepitheleum; outermost layer resting on basement membrane
• Stroma
– Fibrous connective tissue (Stroma) surrounding the glandular tissue.
– Interlobular adipose tissue.
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Cont’d…

46. Cont’d…
• Parenchyma
– Alveoli (10 to100) form each lobule.
– Lobules(20 to40) form each lobe.
– Lobes (15to20) are radially arranged
segments that are each drained by a
duct; all lobes converge at the
nipple.
• Each lobe of the primary gland
terminates in the lactiferous and
empties into the subareolar
ampulla
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47. Cont’d…
• Lactiferous duct opening stratified squamous epithelium.
• Lactiferous sinus epithelial lining
– Two layers of cuboidal cells in the, thereafter becoming a single layer
of columnar or cuboidal cells
– Closely packed Myoepithelial cells.
• Between the epithelial cell layers and the basement membrane
is a network of Myoepithelial cells; these respond to oxytocin
and are responsible for milk ejection during lactation
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48. Cont’d…
1st = Inactive gland
• Sparse glandular component.
• Predominate by duct elements.
• Undergoes cyclical changes (3 part)
2nd = During pregnancy
• lobular–alveolar growth.
• Decrease in fat and CT.
• Alveoli enlarge and start secretion.
• Infiltration with immune cells.
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49. Cont’d…
3rd during lactation
• Alveoli becomes dilated and appear as
saccules.
• Distended by milk and have low basophile
epithelial columnar cells
• Between the alveolar cells and the basal
lamina are about four to six stellate basket
(Myoepithelial) cells. The cells flatten as
secretion increases.
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50. Cont’d…
4th Senescence
• The secretory epithelium atrophies and only a few
remnants of the duct system persist.
• Cystic dilatation of the remaining ducts
• The connective tissue becomes increasingly dense
and homogeneous.
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51. Physiology of breast
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• Hypothalamus-pituitary-ovarian-breast axis

52. Cont’d…
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53. Cont’d…
Physical development
• Estrogen
– Growth and branching of ductal System
– Development of Stroma and fat deposition
• Progesterone
– Dev't of the lobule alveolar system
• synergistically
– Additional growth of lobules
– Budding of alveoli
– Dev't of secretary cells of alveoli
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54. Cont’d…
Secretory development
• HCG, GH, Cortisol, PTH, Prolactin
• Prolactin
– Increase steadily from 5th wk. till delivery.
– Strong lactogenic effect
– hypothalamic control of prolactin is by PIH
• At birth
– sudden decrease in estrogen & progesterone
– An antagonized action of prolactin
– Adequate milk instead of colostrum
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55. Cont’d…
After birth
• The basal level becomes non-pregnant level
• But at each nursing with Nipple – hypothalamic signaling
– Hypothalamic surge of prolactin leading to secretion ( lasting 1 hr.)
• Milk production for several years as far as there is suckling (rate
decrease after 7-9 months)
• If prolactin surge blocked leads to absent of milk with in one week.
• Suppression of ovarian cycle in nursing mothers
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56. Cont’d…
• Ejection (let down) mediated by oxytocin.
• Milk production continues in the alveoli
• Suckling sensory impulse through somatic N nerve
signal for oxytocin secretion breast contraction of
Myoepithelial cells express the milk from the alveoli to
the ducts.
• Many psychogenic factors and generalised SNS stimulation can
inhibit milk ejection
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57. Cont’d…
• Composition of breast milk vs. cows milk
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58. References
1. Brunicardi FC, Anderson DK (2019) Schwartz's Principles of surgery. 11th edition,
NewYork: McGraw-Hill.
2. Jatoi I., Kaufman M., Petit JY (2010) , Atlas of breast surgery, Germany: Springers
3. Moore KL., Persaud TVN., et al (2016) The developing human; clinically oriented
embryology 6th edition, Philadelphia: ELSEVIER
4. Standring S., et al (2016) Grays Anatomy: the anatomical basis of clinical practice,
41st edition, Philadelphia: ELSEVIER.
5. Townsend CM., et al (2018), Sabiston text book of surgery, 20th edition,
Philadelphia: ELSEVIER.
6. Williams NS, et al(2018) Bailey and Love’s Short Practice of Surgery, 27th ed,
NewYork: CRC press.
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59. Thank
you
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