breast anatomy board

Question 1

When do the mammary ridges develop in an embryo?

Answer 1

Fifth or sixth week of gestation.

Question 2

What is the path of the mammary ridge along the ventral aspect of an embryo?

Answer 2

Base of the forelimb (future axilla) to the base of the hindlimb (inguinal area).

Question 3

What is the result of incomplete involution of the mammary ridge?

Answer 3

Accessory breast tissue and supernumerary nipples.

Question 4

Is amastia more commonly unilateral or bilateral?

Answer 4

unilateral

Question 5

What is the cause of unilateral amastia?

Answer 5

Arrested mammary ridge development during the sixth week of fetal development.

Question 6

Where is the most common site of aberrant breast tissue?

Answer 6

axilla

Question 7

Where is the most common site of a supernumerary nipple?

Answer 7

inframammary area

Question 8

Each cluster of alveoli leads to a milk duct that empties into a lactiferous sinus. Each lactiferous sinus drains one lobe of the breast. How many lobes are in the breast?

Answer 8

15 to 25 lobes per breast.

Question 8

The breast overlies which ribs?

Answer 8

Second to sixth.

Question 9

What is the most common bacteria cultured from breast tissue?

Answer 9

Staphylococcus epidermidis.

Question 10

Which vessel provides the dominant blood supply to the breast?

Answer 10

Internal mammary artery

Question 11

The internal mammary artery is a branch of which artery?

Answer 11

Subclavian artery (left)/brachiocephalic artery (right)

Question 12

Usually, what vessel is the largest artery entering the pectoralis major muscle and overlying breast parenchyma?

Answer 12

The second intercostal internal mammary perforator

Question 13

Name three branches of the axillary artery (from medial to lateral) that serve as blood supply to the breast.

Answer 13

Thoracoacromial, lateral thoracic, and thoracodorsal arteries

Question 14

When dissecting the axilla, if you clip the intercostobrachial nerve, where will you lose sensation?

Answer 14

Upper medial aspect of arm and axilla

Question 15

The intercostobrachial nerve is a branch of what nerve?

Answer 15

Lateral branch of the second intercostal nerve

Question 16

Axillary nodes are noted as level I, level II, or level III. What anatomic structure determines their “level”?

Answer 16

Pectoralis minor muscle

Question 17

Where are level I axillary lymph nodes located?

Answer 17

Lateral/below the lower border of pectoralis minor

Question 18

Where are level II axillary lymph nodes located?

Answer 18

Behind pectoralis minor

Question 19

Where are level III axillary lymph nodes located?

Answer 19

Medial/above the upper border of pectoralis minor

Question 20

What is the primary innervation to the nipple–areola complex?

Answer 20

Lateral branch of the fourth intercostal nerve

Question 21

What is the course of the lateral branch of the fourth intercostal nerve?

Answer 21

It pierces the deep fascia in the midaxillary line and takes an inferomedial course within the pectoral fascia. On reaching the midclavicular line, it turns 90◦ and continues through the glandular tissue toward the posterior surface of the nipple

Question 22

What is the normal diameter of the areola complex?

Answer 22

35 to 45 mm

Question 23

What is the function of the Montgomery glands?

Answer 23

They are sebaceous glands that produce a waxy substance to assist with lubrication and protection of the
nipple–areola complex

Question 24

The suspensory ligaments of Cooper attach which structures?

Answer 24

Deep pectoralis fascia to the dermis of the breast

Question 25

What is the lateral margin of the breast parenchyma?

Answer 25

Lateral margin of the latissimus dorsi

Question 26

What is the superior margin of the breast parenchyma?

Answer 26

The clavicle

Question 27

What is the medial margin of the breast parenchyma?

Answer 27

Lateral sternum

Question 28

What is the major component of the anterior axillary fold?

Answer 28

Pectoralis major

Question 29

What is the origin of the pectoralis major muscle?

Answer 29

Medial sternal half of the clavicle and lateral aspect of the sternum/costochondral region, from the sternal notch down to the sixth or seventh costal cartilages

Question 30

The insertion of the pectoralis major tendon lies between which two muscles?

Answer 30

Coracobrachialis (posterior) and deltoid (anterior)

Question 31

Which nerve provides motor innervation to the lateral and inferior pectoralis major muscle?

Answer 31

Medial pectoral nerve

Question 32

The serratus anterior originates from costal attachments of the anterolateral aspects of the first through the eighth ribs. Where does this muscle insert?

Answer 32

Deep medial surface of the scapula

Question 33

What is the innervation to the serratus anterior muscle?

Answer 33

Long thoracic nerve

Question 34

What is the clinical manifestation of injury to the long thoracic nerve?

Answer 34

Winged scapula

Question 35

How can one locate the long thoracic nerve?

Answer 35

Positioned laterally, superficial to the external surface of the serratus anterior muscle in the midaxillary line

Question 36

If the thoracodorsal artery is proximally occluded/ligated, which vessel is capable of providing a significant portion of blood supply to the latissimus dorsi?

Answer 36

Serratus branch of the thoracodorsal artery

Question 37

Which nerves supply innervation to the medial breast?

Answer 37

The second to sixth medial intercostal nerves

Question 38

Which condition is associated with a congenital absence of the pectoralis major muscle, usually the sternal component, as well as breast and areolar hypoplasia?

Answer 38

Poland syndrome

Question 39

Following efferent lymphatic drainage into the deep pectoral nodes and subscapular nodes, which nodes are next in the lymphatic drainage pathway of the breast?

Answer 39

Central axillary nodes and apical axillary nodes

Question 40

Following efferent drainage into the axillary nodes, which nodes are next in the lymphatic drainage pathway of the breast?

Answer 40

Supraclavicular nodes

Question 41

If lymphatic drainage takes a medial pathway (vs. draining into the axilla), which nodes are the primary drainage basin?

Answer 41

Internal mammary nodes/parasternal nodes

Question 42

True/False: Axillary nodes primarily drain the lateral half of the breast, while parasternal nodes drain medial quadrants

Answer 42

False: Dye flow studies report that both the axillary and the parasternal lymphatic groups receive lymph from all quadrants of the breast

Question 43

What aspect of the breast parenchyma supplies lymph to the internal mammary/parasternal nodes?

Answer 43

The entire gland

Question 44

Which hormone is principally responsible for ductal development and maintenance of glandular elements during the reproductive years?

Answer 44

Estrogen

Question 45

Which hormone is principally responsible for lobular development and differentiation of epithelial cells?

Answer 45

Progesterone

Question 46

Which hormone stimulates the differentiation of milk-producing cells and initiates the synthesis of milk components

Answer 46

prolactin

Question 47

In the youthful, non-ptotic breast, where should the NAC be located?

Answer 47

Above the inframammary fold (IMF)

Question 48

In the youthful, nonptotic breast, what is the normal distance between the sternal notch and the nipple?

Answer 48

17 to 21 cm

Question 49

In the youthful, nonptotic breast what is the normal distance between the nipple and the IMF?

Answer 49

7 to 8 cm

Question 50

What is the etiology of a congenital inverted nipple? What is its incidence?

Answer 50

Failure of the mammary pit to elevate above skin level during infancy; 2% to 4%

Question 51

What is Poland syndrome?

Answer 51

Hypoplasia or absence of the ipsilateral breast, absence of the sternal head of the pectoralis major muscle, costal cartilage and rib defects, hypoplasia of subcutaneous tissues of the chest wall, and brachysyndactyly.

Question 52

What is the anatomic abnormality with the tuberous breast deformity?

Answer 52

NAC hypertrophy, constricted breast/lower pole, herniation of breast tissue into NAC

Question 53

What is the difference between skin sparing mastectomy and total skin sparing mastectomy?

Answer 53

The NAC is preserved with total skin-sparing mastectomy