Thoracic Wall

Question 1

Why is the sternum important?

Answer 1

It is a major site for RBC production

Question 2

Which part of the sternum forms the jugular notch?

Answer 2

Manubrium

Question 3

Which part of the sternum contains costal cartilage of the second rib that articulates directly with the manubriosternal joint?

Answer 3

Body

Question 4

Which part of the sternum is cartilaginous at birth and slowly ossifies throughout life?

Answer 4

Xiphoid process

Question 5

What structure is commonly broken during CPR?

Answer 5

Xiphoid process

Question 6

What forms the sternal angle?

Answer 6

The articulation of the manubrium with the body of the sternum

Question 7

What vertebral level is the sternal angle found?

Answer 7

The intervertebral disc between T4 and T5

Question 8

What is the superior opening of the thoracic cage?

Answer 8

The superior thoracic aperture

Question 9

What is the superior thoracic aperture bounded by? (3)

Answer 9

1) Manubrium
2) First rib
3) First thoracic vertebra

Question 10

What is the inferior opening of the thoracic cage?

Answer 10

Inferior thoracic aperature

Question 11

What is the inferior thoracic aperture bounded by? (5)

Answer 11

1) Xiphoid process
2) Costal margin
3) 12th rib
4) Distal end of 11th rib
5) 12th thoracic vertebra

Question 12

What are the true ribs and how do they articulate with the sternum?

Answer 12

Ribs 1-7

Articulate with the sternum directly through their own costal cartilages

Question 13

What are the false ribs and how to they articulate with the sternum?

Answer 13

1) Ribs 8-10: articulate with the sternum indirectly by attaching to the costal cartilage of the rib above
2) Ribs 11 and 12: not connected to the sternum at all

Question 14

What are the typical ribs?

Answer 14

3-9

Question 15

What are the atypical ribs?

Answer 15

1, 2, 10,11, and 12

Question 16

What is the morphology of a typical rib? (6)

Answer 16

Head, neck, tubercle, angle, shaft, costal groove

Question 17

Name the 3 functions of the thoracic cage.

Answer 17

1) Protection of thoracic and upper abdominal organs
2) Muscle attachments
3) Respiration

Question 18

What is the 2nd most important muscle for inspiration?

Answer 18

External Intercostal Muscle

Question 19

O, I, A, N of External Intercostal Muscle

Answer 19

O: lower border of ribs 1 to 11
I: upper border of ribs 2 to 12
A: elevates the ribs in inspiration
N: corresponding intercostal nerve

Question 20

O, I, A, N of External Intercostal Muscle

Answer 20

O: lower border of ribs 1 to 11
I: upper border of ribs 2 to 12
A: elevates the ribs in inspiration
N: corresponding intercostal nerve

Question 21

O, I, A, N of Internal Intercostal Muscle

Answer 21

O: the upperborder of ribs 2 to 12
I: the lower border of ribs 1 to 11
A: depresses the ribs in forced expiration
N: corresponding intercostal nerve

Question 22

O, I, A, N of the Innermost Intercostal Muscle

Answer 22

O: the upper border of ribs 2 to 12
I: the lower of ribs 1 to 11
A: Depresses the ribs in forced expiration
N: corresponding intercostal nerve

Question 23

O, I, A, N of the Subcostalis Muscle

Answer 23

O: inner surface of ribs near their angles
I: the muscle crosses a rib without inserting and then inserts into the rib above that
A: depresses the ribs in forced expiration
N: intercostal nerve

Question 24

O, I, A, N of the Transversus Thoracis Muscle

Answer 24

O: posterior surface of lower sternal body and xiphoid process
I: inner surface of costal cartilages 2 to 6
A: depresses the ribs in forced expiration
N: intercostal nerve

Question 25

What artery and its branches supplies the anterior aspect of the thoracic wall?

Answer 25

Internal thoracic artery

Question 26

Name the branches of the internal thoracic artery. (4)

Answer 26

1) Pericardiacophrenic artery 2) Anterior intercostal arteries 3) Musculophrenic artery 4) Superior epigastric artery

Question 27

What arteries supply the posterior aspect of the thoracic wall? (3)

Answer 27

1) Supreme (superior) intercostal artery 2) Third through eleventh posterior intercostal arteries 3) Subcostal artery

Question 28

What vein drains the anterior aspect of the thoracic wall?

Answer 28

Internal thoracic vein (into the brachiocephalic vein)

Question 29

What vein drains the posterior aspect of the thoracic wall?

Answer 29

Azygos system of veins

Question 30

On the right and left side of the azygos system, what does the 1st posterior intercostal vein drain into?

Answer 30

The brachiocephalic vein

Question 31

On the right side of the azygos system, what does the 2nd and 3rd posterior intercostal veins join together to form?

Answer 31

The superior intercostal vein, which drains into the azygos vein

Question 32

On the right side of the azygos system, what does the 4th through the 11th posterior intercostal veins and subcostal vein drain into?

Answer 32

Directly into the azygos vein

Question 33

On the left side of the azygos system, what does the 2nd and 3rd posterior intercostal veins join together to form?

Answer 33

The superior intercostal vein, which drains into the left brachiocephalic vein

Question 34

On the left side of the azygos system, what does the 4th and 8th posterior intercostal vein join together to form?

Answer 34

The accessory hemiazygous vein, which drains into the azygous vein

Question 35

On the left side of the azygos system, what does the 9th through the 11th posterior intercostal veins and the subcostal vein join to form?

Answer 35

The hemiazygous vein, which drains into the azygos vein

Question 36

The azygous and hemiazygos veins represent the thoracic continuation of which veins?

Answer 36

The right and left ascending lumbar veins

Question 37

What are the two nerves of the thoracic wall?

Answer 37

1) Intercostal nerves- the anterior primary rami of the first 11 thoracic spinal nerves 2) Subcostal nerve- the anterior primary ramus of the 12th thoracic spinal nerve

Question 38

Name the 12 layers of the thoracic wall. (Figure 3.26B)

Answer 38

1) Skin 2) Superficial Fascia 3) Deep Fascia 4) Serratus anterior 5) External intercostal muscle 6) Internal intercostal muscle 7) Innermost intercostal muscle 8) Endothoracic fascia 9) Parietal pleura 10) Pleural cavity 11) Visceral pleura 12) Lung

Question 39

What is the function of the endothoracic fascia?

Answer 39

To prevent the innermost intercostal muscle from rubbing against the parietal pleura

Question 40

What is the thickening of the fascia over the apex of the lung called?

Answer 40

Suprapleural membrane

Question 41

What structures does the typical intercostal space include?

Answer 41

1) Intercostal vein 2) Intercostal Artery 3) Intercostal Nerve

Question 42

What two muscles is the typical intercostal space sandwiched in between?

Answer 42

The internal and innermost intercostal muscles