Anterior Thoracic Wall

Question 1

What are the three muscles of the intercostal space?

Answer 1

1. External intercostals
2. Internal intercostals
3. Innermost intercostals

Question 2

What are the three movements of the thoracic cage? Describe them.

Answer 2

1. increase in vertical diameter (contraction of diaphragm)
2. Bucket Handle movement of ribs - ribs swing out laterally to increase transverse diameter
3. Pump Handle - movement of the ribs when the sternum and anterior ends are raised to increase anteroposterior diameter.

Question 3

What are the parts of a typical intercostal nerve?

Answer 3

white and gray ramus from the ventral rami

then splits into the following branches: rami communicantes, collateral branches, lateral cutaneous branches, and anterior cutaneous branches

Question 4

Where do the posterior intercostal arteries originate from?

Answer 4

the thoracic aorta posteriorly

Question 5

Where do the anterior intercostal arteries arise from?

Answer 5

they are branches of the internal thoracic artery, which is off the subclavian

Question 6

What are the 4 branches from the internal thoracic artery?

Answer 6

the pericardiacophrenic
musculophrenic, which gives off the intercostal arteries in 7-9
superior epigastric
anterior intercostal arteries

Question 7

Where do the anterior intercostal veins drain?

Answer 7

the internal thoracic veins

Question 8

Where do the posterior intercostal veins drain?

Answer 8

azygos and hemiazygos system of veins

Question 9

Which rib pairs actually connect to the sternum and which do not?

Answer 9

1-7 connect
8-10 connect indirectly through costal cartilage
11 and 12 are “false” ribs in that they only connect to the costal cartilage of the rib above.

Question 10

What are the two ways the vertebrae connect to the ribs?

Answer 10

1. through the facet joints directly to the head of the ribs

2. through the costotransverse joints between the tubercle or rib and transverse process

Question 11

What binds the superior thoracic aperture?

Answer 11

the body ot T1, rib 1 and the manubrium

Question 12

What passes through the superior thoracic aperture?

Answer 12

the brachial blexus and the subclavian artery and veins

Question 13

What is the superior thoracic aperture known as CLINICALLY?

Answer 13

the thoracic outlet (even though it’s technically the outlet)

Question 14

What is thoracic outlet syndrome/

Answer 14

it’s when there’s compression of the brachial plexus and/or subclavians in the outlet

Question 15

What binds the inferior thoracic aperture?

Answer 15

body of T12, costal margin, xiphisternal joint

Question 16

What does the inferior thoracic aperture represent?

Answer 16

the attachment of the diaphragm

Question 17

What are the sections fo the sternum?

Answer 17

the manubrium, body and xiphoid process

Question 18

How does the sternum develop?

Answer 18

from 6 separate ossification centers - most of which fuse around age 25 (xiphoid is last at age 35)

Question 19

The sternal angle is what type of joint?

Answer 19

a symphysis - secondary cartilaginous joint where the bones are united by fibrocartilage

Question 20

The xiphisternal junction is what type of joint?

Answer 20

a synchondrosis - primary cartilaginous joint where the bones are united by hyaline cartilage temporarily and then converts to bone

Question 21

What disc space lies posterior to the sternal angle?

Answer 21

T4-T5

Question 22

What number is the intercostal space below the sternal angle?

Answer 22

the 2nd intercostal space

Question 23

What happens with the trachea at the sternal angle? What part of the aorta is located posterior ot the sternal angle? WHat does the superior vena cava do at the sternal angle? What does the sternal angle do to the mediastinum?

Answer 23

trachea bifurcates
aortic arch
it enters the pericardium
divides it into inferior and superior

Question 24

What is the weakest part of the rib? Which ribs are most frequently fractured?

Answer 24

just anterior to the angle

the middle ribs are most frequently fractured

Question 25

What is contained in the costal groove just under the rib?

Answer 25

the intercostal VAN (vein, artery, nerve)

Question 26

What vertebrae does rib #4 articulate with?

Answer 26

T4 (via the facet and the tubercle) and T3 (via the facet)

Question 27

What happens when the external intercostals contract?

Answer 27

they cause the lungs to elevate, resulting in forced inspiration

Question 28

The external intercostal muscle layer is incomplete anteriorly or posteriorly?

Answer 28

anteriorly - replaced by the external intercostal membrane

Question 29

What happens when the internal intercostal contracts?

Answer 29

they depress the ribs, causing forced expiration

Question 30

The internal intercostal muscles are incomplete anteriorly or posteriorly?

Answer 30

posteriorly

Question 31

What muscles keep the intercostal spaces rigid and elevate or depress the ribs?

Answer 31

subcostals

Question 32

What's the primary movement of inspiration?

Answer 32

contraction of the diaphragm increasing the vertical dimension

Question 33

What major artery can be seen lateral to the sternum within the intercostal spaces?

Answer 33

the internal thoracic artery

Question 34

What is the internal thoracic artery a branch of?

Answer 34

subclavian

Question 35

inferiorly, the internal thoracic artery branches to form what two arteries?

Answer 35

the superior epigastric and musculophrenic arteries

Question 36

The ventral ramus of the 12th nerve forms what?

Answer 36

the subcostal nerve

Question 37

Each intercostal nerve is connected to a ganglion of the sympathetic trunk via what?

Answer 37

rami communicantes

Question 38

THe white ramus conteys what fibers? How about the gray ramus?

Answer 38

``` white = preganglionic sympathetic to the ganglion gray = postganglionic away from the ganglion ```

Question 39

THe intercostal nerves carry motor fibers to the muscles and sensory fibers from the skin and ....

Answer 39

partietal pleura

Question 40

The anterior cutaneous branches of the T7-T12 intercostal nerves carry sensation and motor to what?

Answer 40

the abdominal muscles and skin

Question 41

The outer wall of the pericardium is called what?

Answer 41

the fibrous pericardium

Question 42

The inner layer of pericardium is what? What are it's two layers?

Answer 42

the serous pericardium parietal is attached to the inner aspect of the fibrous pericardium and the visceral pericardium (epicardium) is attahed tot he heart

Question 43

What layer of the pericardium reflects back over the great vessels?

Answer 43

visceral

Question 44

What sinus lies behind the aorta and pulmonary trunk? What is the clinical significance?

Answer 44

the transverse sinus you can clamp it to stop blood flow to the heart during surgery

Question 45

What sinus is formed by the pericardial reflections on the inferior vena cava and pulmonary veins?

Answer 45

oblique sinus