THE BREAST

I. Introduction/General Information

A. Embryologically: belong to integument

B. Functionally: part of reproductive system

1. Respond to sexual stimulation

2. Feed babies

Breast, continued …

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 Attachment1. Lateral aspect of pectoral region

2. Located between ribs 3 and 6/73. Extend form sternum to axilla4. Surrounded by superficial fascia5. Rest on deep fascia

Breast Anatomy

Position & attachment, continued ….

6. Fixed to skin & underlying fascia by fibrous C.T. bandsa. Cooper’s (Suspensory)

Ligamentsb. Ligaments may retract when

breast tumors are present

Cooper’s Suspensory Ligaments

Position & attachment, continued …

6. Left breast is usually slightly larger

7. Base is circular, either flattened or concave

8. Separated from pectoralis major muscle by fascia, retromammary space

Retromammary Space

Retromammary Space

Anatomy, continued …

B. Structure

1. Outer surface convex, skin covered

2. Nipple:

a. At fourth intercostal space

b. Small conical/cylindrical prominence below center

Nipple location

4th intercostal

space

Structure, continued …

c. Surrounded by areola: pigmented ring of skin

d. Thin skinned region lacking hair, sweat glands

e. Contains areolar glands

Structure, continued …

3. Areola: contains dark pigment that intensifies with pregnancy

a. Circular and radial smooth muscle fibers

b. Cause nipple erection

Areola

Structure, continued …

4. Each breast consists of ~ 20 lobes of secretory tissue

a. Each lobe has one lactiferous ductb. Lobes (and ducts) arranged radially c. Embedded in connective tissue &

adipose of superficial fasciad. Lobes composed of lobulese. Lobules comprise alveoli

Lobes and Lobules

Structure, continued …

5. Excretory (lactiferous) ducts converge toward areola

a. Form ampullae (collection sites of lactiferous sinuses)

b. Ducts become contracted at base of nipple

Excretory (lactiferous) ducts

Structure, continued …

6. Secretory epitheliuma. Changes with hormonal signalsb. Onset of menstruationc. Pregnancy (glands begin to

enlarge at 2nd month)d. After birth, 1st secretion is

colostrom (contain antibodies)

Structure, continued …

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

“Tail of Spence”

Axillary Tail

Structure, continued …

8. Fatty Tissue: surrounds surface, fills spaces between lobes

a. Determines form & size of breast

b. No fatty deposit under nipple & areola

Breast: Fatty Tissue

Structure, continued …

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

Vessels & Nerves, continued …

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

Subclavian a.

Axillary a.

External mammary (thoracic) a.

Internal mammary (thoracic) a.

Arterial Supply to the Breast

Vessels & Nerves, continued …

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

Veins draining the Breast

Subclavian vein

External mammary vein

Breast Anatomy, con’t…

3. Innervation: derived from:

a. anterior & lateral cutaneous nerves of thorax

b. spinal segments T3 – T6

Structure, continued …

4. Lymphatics: clinically significant!a. Glandular lymphatics drain into

anterior axillary (pectoral) nodes central axillary nodes

apical nodes deep cervical nodes

subclavicular (subclavian) nodesb. Medial quadrants drain into

parasternal nodes

Subclavian nodes

Axillary nodes

Lateral pectoral

nodes

Parasternal nodes

Lymph Nodes of the Breast

Lymphatics, continued …

c. Superficial regions of skin, areola, nipples:

-form large channels & drain into pectoral nodes

d. NOTE: axillary nodes also drain lymph from arm

Lymph Nodes and Lymph Drainage

Axillary Nodes

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

Subdiaphragmatic Lymph Channels

Channels to Contralateral Breast

Axillary Lymph Channels

Major Routes of Metastasis

Structure, continued …

D. Anomalies1. Inverted nipple: congenital or due

to cancer2. Ectopic nipple:

a. “polythelia” or “hyperthelia”

b. additional nipples along milk line

3. Amastia 4. Micromastia

Anomalies, continued …

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

Diseases of the breast, continued …

3. Endocrine influence

a. Menstruation – tenderness from fluid engorgement

b. Post-menopause 1) decrease of fibro-cystic disease

2) increase in cancerc. Pregnancy

Diseases of the Breast, continued …

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

Symptoms & Signs, continued …

5. Retraction sign: “dimpling” involving skin, nipple or areola6. Mobility of mass

a. Benign = movable 1) not attached 2) not invasive

b. Malignant = attached 1)May grow into bone

Symptoms & Signs, continued …

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 conditions1. Infection = usually during or after

lactationa. Recurrent, subareolar abscessb. TB of the breast

2. Trauma = contusion3. Hypertrophy = seen in either sex

at adolescencea. Gynecomastia = in males

Hypertrophy, continued …

b. Other causes

1) testicular or pituitary tumor2) cirrhosis 3) hypogonadism = not enough

testosterone4) estrogen administration for

prostate cancer

Benign Conditions, continued

4. Tumors & cystsa. Fibroadenoma =

most common benign breast

tumor

Tumors and Cysts, con’t…

b. Breast Cyst

1. Benign

2. May be aspirated

if large

Benign conditions, continued …

c. Fibrocystic breast changes

1) 20%+ of premenopausal women 2) discomfort, cysts3) treatment rarely required 4) More likely to not detect a developing cancer

Tumors & cysts, continued ….

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 cancera. 1/6 in Orange Countyb. 1/5 in San Francisco

3. Generally no discomfort

Progression to Breast Cancer

Carcinoma of breast, continued …

4. Physical signs:a. Slowly growing, painless massb. May demonstrate retracted nipplec. May be bleeding from nippled. May be distorted areola, or breast contoure. Skin dimpling in more advanced stages with retraction of

Cooper’s ligaments

Physical signs, continued …

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

Breast Cancer, con’t…

5. Common sites for metastasisa. Lungs & pleurab. Skeleton system (skull, vertebral column,

pelvis)c. Liver

6. Atypical carcinomasa. Inflammatory carcinoma (hormonal,

chemotherapy) b. Paget’s disease of the breast