Breast Anatomy ppt

Breast Anatomy Presentation

A part of presentation :

I. Introduction/General Information:
A. Embryologically: belong to integument
B. Functionally: part of reproductive system
1. Respond to sexual stimulation
2. Feed babies
C. Modified apocrine sweat glands
- apex of cell becomes part of secretion and breaks off
D. Present in males and females

II. Anatomy
A. Position and Attachment
1. Lateral aspect of pectoral region
2. Located between ribs 3 and 6/7
3. Extend form sternum to axilla
4. Surrounded by superficial fascia
5. Rest on deep fascia
6. Fixed to skin & underlying fascia by fibrous C.T. bands
a. Cooper’s (Suspensory) Ligaments
b. Ligaments may retract when breast tumors are present
7. Left breast is usually slightly larger
8. Base is circular, either flattened or concave
9. Separated from pectoralis major muscle by fascia, retromammary space

B. Structure
1. Outer surface convex, skin covered
2. Nipple:
a. At fourth intercostal space
b. Small conical/cylindrical prominence below center
c. Surrounded by areola: pigmented ring of skin
d. Thin skinned region lacking hair, sweat glands
e. Contains areolar glands
3. Areola: contains dark pigment that intensifies with pregnancy
a. Circular and radial smooth muscle fibers
b. Cause nipple erection
4. Each breast consists of ~ 20 lobes of secretory tissue
a. Each lobe has one lactiferous duct
b. Lobes (and ducts) arranged radially
c. Embedded in connective tissue & adipose of superficial fascia
d. Lobes composed of lobules
e. Lobules comprise alveoli
5. Excretory (lactiferous) ducts converge toward areola
a. Form ampullae (collection sites of lactiferous sinuses)
b. Ducts become contracted at base of nipple
6. Secretory epithelium
a. Changes with hormonal signals
b. Onset of menstruation
c. Pregnancy (glands begin to enlarge at 2nd month)
d. After birth, 1st secretion is colostrom (contain antibodies)
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
8. Fatty Tissue: surrounds surface, fills spaces between lobes
a. Determines form & size of breast
b. No fatty deposit under nipple & areola

C. Vessels & nerves

1. Arteries: derived from thoracic branches of three pairs of arteries
a. Axillary arteries
1) continuous with subclavian a.
2) gives rise to external mammary ( = lateral thoracic) artery
b. Internal mammary (thoracic) arteries
1) first descending branch of subclavian artery 2) supply intercostal spaces & breast
3) used for coronary bypass surgery
c. Intercostal arteries:
1) numerous branches from internal & external mammary arteries
2) supply intercostal spaces & breast

2. Veins:
a. form a ring around the base of the nipple (“circulus venosus”)
b. Large veins pass from circulus venosus to circumference of mammary gland, then to
c. External mammary v to axillary v or
d. Internal mammary v to subclavian v

3. Innervation: derived from:
a. anterior & lateral cutaneous nerves of thorax
b. spinal segments T3 – T6

4. Lymphatics: clinically significant!
a. Glandular lymphatics drain into
anterior axillary (pectoral) nodes –>
central axillary nodes –>
apical nodes –>
deep cervical nodes –>
subclavicular (subclavian) nodes
b. Medial quadrants drain into parasternal nodes
c. Superficial regions of skin, areola, nipples:
-form large channels & drain into pectoral nodes
d. NOTE: axillary nodes also drain lymph from arm

Routes of Metastasis :
- From medial lymphatics to parasternal nodes
Then to mediastinal nodes
- Across the sternum in lymphatics to opposite side via cross-mammary pathways
Then to contralateral breast
- From subdiaphragmatic lymphatics to nodes in abdomen
Then to liver, ovaries, peritoneum

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
5. Macromastia
6. Gynecomastia
a. breast development of male in areolar region
b. noted in males who smoke marijuana at puberty

III. Diseases of the Breast :
A. Most are readily detectable

B. Etiology unknown, influencing factors
1. Sex
2. Heredity
3. Endocrine influence
a. Menstruation – tenderness from fluid engorgement
b. Post-menopause
1) decrease of fibro-cystic disease
2) increase in cancer
c. Pregnancy

C. General symptoms & signs
1. Nipple discharge
a. always significant if not pregnant.
b. May be due to benign pituitary tumor.
2. Local pain, tenderness
3. Duration of lesion
4. Size, rate of growth
5. Retraction sign: “dimpling” involving skin, nipple or areola
6. Mobility of mass
a. Benign = movable
1) not attached
2) not invasive
b. Malignant = attached
1)May grow into bone
7. Consistency of mass
a. Cysts = fluctuant; compressible
b. Fibroadenoma = rubbery
c. Carcinoma = firm, hard (like gravel)
8. Axillary area lymph node enlargement

D. Benign breast conditions :

1. Infection = usually during or after lactation
a. Recurrent, subareolar abscess
b. TB of the breast

2. Trauma = contusion

3. Hypertrophy = seen in either sex at adolescence
a. Gynecomastia = in males
b. Other causes
1) testicular or pituitary tumor
2) cirrhosis
3) hypogonadism = not enough testosterone
4) estrogen administration for prostate cancer

4. Tumors & cysts
a. Fibroadenoma = most common benign breast tumor
b. Breast Cyst
1. Benign
2. May be aspirated if large
c. Fibrocystic breast changes
1) 20%+ of premenopausal women
2) discomfort, cysts
3) treatment rarely required
4) More likely to not detect a developing cancer
d. Intraductal papilloma
- may produce “chocolate” or bloody discharge from nipple
e. Lipoma: common
- fatty tumors

E. Carcinoma of the breast :
1. Most common malignant tumor among women
2. 1/8 of women will develop breast cancer
a. 1/6 in Orange County
b. 1/5 in San Francisco
3. Generally no discomfort
4. Physical signs:
a. Slowly growing, painless mass
b. May demonstrate retracted nipple
c. May be bleeding from nipple
d. May be distorted areola, or breast contour
e. Skin dimpling in more advanced stages with retraction of Cooper’s ligaments
f. Attachment of mass
g. Edema of skin
1) with “orange skin” appearance (peau d’orange)
2) due to blocked lymphatics
h. Enlarged axillary or deep cervical lymph nodes
5. Common sites for metastasis
a. Lungs & pleura
b. Skeleton system (skull, vertebral column, pelvis)
c. Liver
6. Atypical carcinomas
a. Inflammatory carcinoma (hormonal, chemotherapy)
b. Paget’s disease of the breast

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Tags: the breast anatomy , breast slideshow , breast Lobes and Lobules , Excretory (lactiferous) ducts , Breast: Fatty Tissue , Arterial Supply to the Breast , Major Routes of Metastasis , Progression to Breast Cancer

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