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