Pectoral Region

Question 1

Clavicle

Answer 1

elevation medially of sternoclavicular joint

laterally to acromion process

Question 2

jugular (suprasternal) notch

Answer 2

superior border of manubrium

Question 3

median furrow

Answer 3

between sternal attachments of pectorals major muscle

Question 4

sternal angle

Answer 4

angle between manubrium and sternum at point of junction with second rib

Question 5

xiphoid process

Answer 5

inferior body of sternum; mainly cartilage

Question 6

nipple

Answer 6

located at mid-clavicular line at 4th intercostal space

not reliable landmark in adult female

Question 7

anterior axillary fold

Answer 7

lateral border of pectoralis major

Question 8

deltopectoral triangle

Answer 8

space at junction of clavicle with the deltoid and pectoralis major muscle

Question 9

deltopectoral groove

Answer 9

between deltoid and pectoralis major muscle; leads to deltopectoral triangle

Question 10

Superficial structures of pectoral region

Answer 10

• Supraclavicular nerves (C3, C4)- from cervical plexus
• anterior and lateral cutaneous branches of ventral rami of thoracic spinal nerves
• anterior perforating arteries of internal thoracic artery
• lateral cutaneous branches from posterior intercostal arteries
• cephalic vein

Question 11

Cephalic vein

Answer 11

• travels between deltoid and pectoralis major
• courses superiorly and enters deltopectoral triangle
• dives deep and pierces costocoracoid membrane to join axillary vein

Question 12

mammary glands are:

Answer 12

• present in both sexes
  -rudimentary in prepubescent females and male
  -hormonal changes in female change structure of gland
  -modified sweat glands
  -contained within superficial connective tissue
  (no fibrous capsule or specialized vascular, nerve, or lymph supply- gets whats around it bc modified sweat gland)

Question 13

Changes in breast

Answer 13

1. puberty- increase in number of ducts and proliferation of glands
2. increase in fat deposition throughout life
3. menstrual cycle get swelling and proliferation of glands- regress if no pregnancy; if pregnancy tissue increases
4. develop along milk line (can find extra nipples along this line)
5. located between 2nd and 6th ribs from lateral border of sternum to anterior or midaxillary line

Question 14

axillary tail of breast

Answer 14

superolateral extension of break tissue

Question 15

Description of breast

Answer 15

• conical and smooth
• areola=circular pigmented area
• elevated due to presence of areolar glands (sebaceous and rudimentary milk glands)

Question 16

Glandular structure of breasts

Answer 16

• 15-20 lobes of tubulo-aveolar glands
• lobes are pyramid shaped; apex towards nipple
• lobe drained by lactiferous duct that opens to nipple
• lactiferous duct expands to form lactiferous sinus (storage area for secreted products)

Question 17

Supported structure for breasts

Answer 17

• each lobe surrounded by connective tissue
• mammary gland surrounded by loosely organized connective tissue
• mammary gland rests on deep fascia covering pectoralis major and serratus anterior
• fat distributed between glandular tissue and skin

Question 18

Cooper’s ligaments

Answer 18

collagen bundles within superficial fascia and run between skin and deep fascia; supportive structure for breasts
AKA suspensory ligaments

Question 19

smooth muscle layer of breast

Answer 19

between nipple and areola
acts as sphincter for excretory ducts
rhythmic contraction helps empty lactiferous ducts

Question 20

Internal thoracic artery

Answer 20

sends perforating arteries through intercostal space to supply breast area medially

Question 21

lateral thoracic artery

Answer 21

2nd portion of axillary artery - supply breast tissue laterally by direct branches

Question 22

anterior and lateral cutaneous branches of intercostal arteries 3-5

Answer 22

enter gland from deep side of breast tissue

Question 23

Veins of breasts

Answer 23

venae comitantes of arterial supply

tributaries to internal thoracic, lateral thoracic, and intercostal veins

Question 24

metastasis of breast cancer

Answer 24

intercostal veins that return blood from breast tissue enter into azygos vein that communicates with batson’s plexus

Question 25

Lymphatic drainage

Answer 25

• follows venous drainage
• 75% drains to axillary lymph nodes
• 25% to parasternal nodes internal to thorax paralleling internal thoracic artery
• drainage also to opposite breast, supraclavicular, and superficial abdominal areas

Question 26

pectoralis major

Answer 26

O- Medial inferior border of clavicle, manubrium, sternum, costal cartilage 2-6, external abdominal oblique aponeurosis
I- crest of the greater tubercle of the humerus
A- adducts and medially rotates the humerus; clavicular head flexes the humerus
N- medial and lateral pectoral nerve

Question 27

pectoralis minor

Answer 27

O- outer surface of ribs 3-5 (or 2-4)
I- coracoid process of the scapula
A- protracts and depresses the scapula and functions as accessory muscle of inspiration
N- medial pectoral nerve

Question 28

Subclavius

Answer 28

O- upper border of 1st rib and costal cartilage
I- inferior surface of clavicle
A- pulls lateral end of clavicle downward and forward to resist excessive shoulder elevation and protraction
N- nerve to subclavius

Question 29

Clavipectoral fascia

Answer 29

envelops the subclavius and pectoralis minor muscles
divided into 2 parts:

1. Costocoracoid membrane
   - upper portion of the clavipectoral fascia (designating medial and lateral attachments) which spans the interval between the subclavius and pectoralis minor muscles
2. Suspensory ligament of the axilla
   - lower portion of the clavipectoral fascia after it sweeps from both sides of the pectoralis minor to form single thickened sheet which terminates by fusing with axillary fascia at the floor of the axilla
   * **provides dome like configuration to the floor of axilla

Question 30

Costocoracoid

Answer 30

pierced by three structures:

1. Cephalic vein
2. Thoracoacromial artery
3. Lateral pectoral nerve