anatomythe breast

7/30/2019 AnatomyThe Breast

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Surgical anatomy of the breast

by

NawneetPG of surgery,

Chalmeda AnandRao Institute ofMedical Sciences, Karimnagar


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Embryologically: belong to integumentFunctionally: part of reproductive

system--- Feeds babies


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C. Modified apocrine sweat glands

- apex of cell becomes part of secretion

and breaks off

D. Present in males and females


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Position and Attachment

1. Lateral aspect of pectoral region

2. Located between 2ed and 6th ribs

3. Extends from lateral border of

sternum to anterior axillary line

4. Surrounded by superficial fascia5. Rests on deep fascia


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Surgical extension

From Midline to edge of latissmus dorsimuscle

Clavicle to 7th or 8th rib


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Breast Anatomy


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6. Left breast is usually slightly larger

7. Base is circular, either flattened or

concave

8. Separated from pectoralis majormuscle by fascia


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Nipple:

At fourth intercostal space Small conical/cylindrical prominence below

center

Contains smooth muscle fibres arranged

concentrically and longitudinally

Surrounded by thin pigmented skinareola

No hair and sweat glands


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3. Areola: contains dark pigment that

intensifies with pregnancy

a. Circular and radial smooth muscle

fibers

b. Cause nipple erection

c. Contains numerous sweat and sebaceous

glandsenlarge during pregnancyhelps in

lubrication


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4. Each breast consists of 20 lobesof secretory tissue

a. Each lobe has one lactiferous duct

b. Lobes (and ducts) arranged radiallyc. Embedded in connective tissue &

adipose of superficial fascia

d. Lobes composed of lobules

e. Lobules comprise alveoli


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5. lactiferous ducts converge toward

areola and

a. form ampullae--collection siteslactiferous sinuses

b. Ducts become contracted at base ofnipple


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6. Secretory epithelium

a. Changes with hormonal signals

b. Onset of menstruationc. Pregnancy ---glands begin to

enlarge at 2nd month

d. After birth, 1st secretion is

colostrom --contain antibodies


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7. Tail of Spence = axillary tail

a. prolongation of upper, outer

quadrant in axillary direction

b. Passes under axillary fascia

c. May be mistaken for axillary lymph

nodes


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8. Fatty Tissue: surrounds surface, fills

spaces between lobes

a. Determines form & size of breast

b. No fatty deposit under nipple &

areola


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ARTERIAL SUPPLY

ARTERIAL

INTERNAL

MAMMARY

LATERAL BR. OF.INTERCOSTAL

ARTERIES

LATERAL THORACIC

Subclavian a.

External

mammary

(thoracic) a.

.


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2. Veins:a. form a ring around the base of the

nipple --circulus venosusb. Large veins pass from circulus

venosus to circumference of

mammary gland, then to

c. External mammary vto axillary v or

d. Internal mammary vto subclavian v


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3. Innervation: derived from:

a. anterior & lateral cutaneousnerves of thorax

b. spinal segments T3 T6


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LYMPHATIC DRAINAGE

AXILLARY

LATERAL

ANTERIOR

POSTERIOR CENTRAL

INTERPECTORAL

APICAL

INT. MAMMARY

SUPRACLAVICULAR


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Lymphatic drainage-- clinical

significance

a. Glandular lymphatics drain into

anterior axillary (pectoral) nodescentral axillary nodes apical

nodes

deep cervical nodessubclavicular (subclavian) nodes


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b. Medial quadrants drain into

parasternal nodes

c. Superficial areas , areola and

nipplepectoral nodes

. sentinel lymph node is the first

node draining from tumour bearing

area


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Routes of Metastasis

From medial lymphatics to parasternalnodes--Then to mediastinal nodes

Across the sternum in lymphatics to

opposite side via cross-mammary

pathways--Then to contralateral breast

From subdiaphragmatic lymphatics tonodes in abdomen---Then to liver,

ovaries, peritoneum


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Subdiaphragmatic Lymph Channels

Channels to Contralateral Breast

Axillary Lymph Channels

Major Routes of Metastasis


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D. Anomalies

1. Inverted nipple: congenital or due

to cancer

2. Ectopic nipple:

a. polythelia or hyperthelia

b. additional nipples along milk line

3. Amastia

4. Micromastia


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5. Macromastia

6. Gynecomastia

a. breast development of male in

areolar region

b. noted in males who smokemarijuana at puberty

7. Supernumerary breasts along milk line


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axilla

Pyramidal shape

Apex--Base 4 walls-ant, post. , med., lateral

Containing

Artery and vein

lymph nodes

Long thoracic and intercostobrachial nerves

Fat , fascia


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Axilla-diagram


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anatomythe breast

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