Pectoral and Axillary Regions

Question 1

What four bony parts makes up the pectoral region?

Answer 1

Clavicles
Sternum (manubrium, body, xiphoid)
Ribs
Scapula

Question 2

Which region are ribs found in? What do they articulate with?

Answer 2

Found in thoracic region

Articulate with vertebra posteriorly and sternum anteriorly

Question 3

Which are the atypical ribs?
Which ones are true ribs? What makes them true?
Which ones are false ribs? What makes them false?
Which ones are floating ribs?

Answer 3

Atypical=1, 2, 11 & 12
True= 1-7 (vertebrocostal: each rib has its own cartilagenous attachment to sternum–no sharing cartilage bw ribs)
False=8-10 (vertebrochondral: coverges with rib 7 and doesn’t directly attach to sternum like the true ribs)
Floating= Dont attach to sternum, only attach to vertebra posteriorly

Question 4

Which rib attaches to xiphosternal joint?

Answer 4

7th rib

Question 5

Which part of vertebra attaches to head of rib? Which part attaches to tubercle of rib?

Answer 5

Demifacet attaches to head, transverse facet on transverse process attaches to tubercle of rib

Question 6

What attaches at the angle of the rib?

Answer 6

intrinsic back musles

Question 7

Mammary glands are _____

Answer 7

modified sweat glands

Question 8

Retromammary space is potential space between ____ and ____

Answer 8

breast and pectoral fascia

Question 9

The breast is what kind of structure? What is the breast innervated by?

Answer 9

Cutaneous structure, modified sweat gland that rests on pectoral fascia (above pec major)
innervated by intercostal nerves

Question 10

What ligament attaches the breast to the dermis of overlying skin?

Answer 10

Suspensory ligament (Cooper’s ligament)

Question 11

What converges on the nipple? What opens at the nipple?

Answer 11

Mammary gland lobules converge on nipple

15-20 lactiferous ducts open at nipple which is surrounded by pigmented areola

Question 12

Arterial supply of breast tissue?

Answer 12

mammary branches from anterior intercostal, lateral thoracic and internal thoracic arteries

Question 13

venous drainage of breast tissue?

Answer 13

mainly to axillary vein via lateral thoracic veins and medial mamary veins
some drainage to internal thoracic vein via anterior intercostal veins

Question 14

Why is lymphatic drainage to breast tissue important? where is most of the lymph from breast tissue drained into? What are the other 2 routes it can drain lymph?

Answer 14

Bc of its role in metastasis of cancer cells
>75% of lymph from breast drains into axillary lymph nodes (pectoral, central, apical)
remaining drains into parasternal and abdominal lymph nodes
The nipple, areola and lactiferous lobules drain into subareolar lymph nodes

Question 15

Innervation of breast tissue

Answer 15

mainly from anterior and lateral branches of 4th-6th intercostal nerves
some innervation from supraclavicular nerve branches and other intercostal nerves

Question 16

Polymastia & polythelia

Answer 16

Supernumerary breasts or nipples

Question 17

What muscles lie within the clavipectoral fascia?

Answer 17

Pec MINOR and subclavius

Question 18

What muscles make up the delto/clavipectoral triangle? what major structure lies in this triangle?

Answer 18

Deltoid, pec MAJOR and clavicle

the confluence of axillary vein and subclavian vein becoming cephalic vein?? (check answer)

Question 19

What structures lie within the superficial fascia of pectoral region?

Answer 19

Platysma
supraclavicular nerves
anterior and lateral branches of intercostal nerves

Question 20

Borders and structures of deltopectoral triangle

Answer 20

Borders: deltoid, pec major and middle 3rd of clavicle
Structures: cephalic vein, deltopectoral lymph nodes, deltoid branch of thoracoacromial a (from axillary a)

Question 21

Clavipectoral fascia invests what muscles? Where does the fascia attach? What neurovascular strucures are there/peirce it? What does it become?

Answer 21

Invests subclavius and pec minor
attaches to clavicle and anterior thoracic wall
cephalic vein, thoracolumbar a and lateral pectoral nerves pierce it
becomes suspensory ligament of axilla

Question 22

What four muscles are found in the pectoral region? What (generally speaking) innervates them?

Answer 22

Pec major, pec minor, subclavius, serratus anterior

Innervated by ventral rami of spinal nerves via branches of brachial plexus