10.24.16 Overview of the Thorax

Question 1

What are the three major functions of the thoracic wall?

Answer 1

1. Protection of contents in the thoracic cavity and upper abdominal cavity
2. Respiration
3. Attachment for skin, fascia, and overlying muscles of the neck, thorax, upper limbs, abdomen, and back

Question 2

What are the boundaries of the thoracic cage?

Answer 2

Anterior: Sternum, costal cartilage
Lateral: Ribs
Posterior: Thoracic vertebrae and IV discs

Question 3

The thoracic cage is formed by ___ pairs of ribs, the manubrium, costal cartilages, and 12 ___.

Answer 3

12; thoracic vertebrae

Question 4

What forms the thoracic wall?

Answer 4

The thoracic cage, skin, associated fascia, and muscles

Question 5

The thoracic vertebrae have unique long, inferiorly angled ___.

Answer 5

Spinous processes

Question 6

Where are the costal facets located?

Answer 6

On the transverse processes

Question 7

Where are demifacets located?

Answer 7

Laterally on the bodies of T2-T9

Question 8

Which rib does the superior demifacet articulate with? The inferior demifacet?

Answer 8

Superior demifacet articulates with the head of the rib of the same number; inferior demifacet articulates with the head of the rib inferior to it (+1)

Question 9

The superior articular facet of the rib head articulates with the vertebra ___. The inferior articular facet of the rib head articulates with the vertebra ___.

Answer 9

Above; of the same number as the rib

Question 10

What does the crest of the head of the rib attach to?

Answer 10

The intra-articular ligament at most of the costovertebral joints

Question 11

What does the crest of the neck of the rib attach to?

Answer 11

Superior costotransverse ligament

Question 12

What does the tubercle of the rib attach to?

Answer 12

Costotransverse ligaments

Question 13

What does the tubercle articulate with? Which vertebra (#)?

Answer 13

Transverse costal facet; same numbered vertebra

Question 14

What are the true ribs?

Answer 14

1st-7th ribs

Question 15

What are the false ribs?

Answer 15

8th-10th ribs

Question 16

What are the floating ribs?

Answer 16

11th-12th ribs

Question 17

What is a true rib?

Answer 17

Inserts onto the sternum

Question 18

What is a false rib?

Answer 18

Does not insert onto the sternum on their own (come to a common place)

Question 19

What is a floating rib?

Answer 19

Does not articulate at all with the sternum anteriorly

Question 20

What is atypical about the 1st rib?

Answer 20

Has a scalene tubercle (anterior scalene attachment); single facet for articulation with T1 only

Question 21

What is atypical about the 2nd rib?

Answer 21

Tubercle for origin of serratus anterior

Question 22

What is atypical about the 10th rib?

Answer 22

Only one facet for articulation with only one vertebra

Question 23

What is atypical about the 11th and 12th ribs?

Answer 23

No necks or tubercles; free floating; articulate with only one vertebra

Question 24

What are the three parts of the sternum?

Answer 24

1. Manubrium
2. Body
3. Xiphoid process

Question 25

Manubrium is found at the level of the bodies of which vertebrae?

Answer 25

T3 and T4

Question 26

The body of the manubrium is formed by 4 ___.

Answer 26

Sternebra

Question 27

The body of the manubrium is located at the level of which vertebrae?

Answer 27

T5-T9

Question 28

The xiphoid process is located at the level of which vertebrae?

Answer 28

T10

Question 29

The jugular (suprasternal) notch is palpated at the ___ vertebral level.

Answer 29

T2

Question 30

The sternal angle (of Louis) is palpated at the ___ vertebral level.

Answer 30

T4

Question 31

Communication occurs between the thoracic cavity, the neck, and the abdomen through ___ and ___.

Answer 31

Superior and inferior thoracic apertures, respectively

Question 32

What are the boundaries of the superior thoracic aperture?

Answer 32

T1, the first ribs/cartilages, and the superior border of the manubrium

Question 33

What structures pass through the superior thoracic aperture?

Answer 33

Trachea, esophagus, nerves and blood vessels supplying/draining the head, neck, and upper extremities

Question 34

What are the boundaries of the inferior thoracic aperture?

Answer 34

T12, the 11th and 12th pairs of ribs, costal cartilages of ribs 7-10, and the xiphisternal joint

Question 35

Which of the thoracic apertures is more spacious?

Answer 35

Inferior thoracic aperture

Question 36

What separates the thorax from the abdomen?

Answer 36

Diaphragm

Question 37

Because of the closing off of the thoracic outlet by the diaphragm, structures pass to and from the thorax to the abdomen via what three openings?

Answer 37

1. Esophageal hiatus 2. Aortic hiatus 3. Inferior vena caval hiatus

Question 38

What are the muscles of the thoracic cage?

Answer 38

1. External intercostal 2. Internal intercostal 3. Innermost intercostal 4. Transversus thoracis

Question 39

What is the origin of external intercostal?

Answer 39

Lower border of ribs

Question 40

What is the insertion of external intercostal?

Answer 40

Upper border of rib below rib of origin

Question 41

What innervates external intercostal?

Answer 41

Intercostal nerves

Question 42

What is the function of external intercostal?

Answer 42

Supports intercostal spaces in inspiration and expiration, elevates ribs in inspiration

Question 43

What is the origin of internal intercostal?

Answer 43

Lower border of ribs

Question 44

What is the insertion of internal intercostal?

Answer 44

Costal cartilage and edge of costal groove of rib above rib of origin

Question 45

What innervates internal intercostal?

Answer 45

Intercostal nerves

Question 46

What is the function of internal intercostal?

Answer 46

Prevents pushing out or drawing in of intercostal spaces in inspiration and expiration, lowers ribs in forced expiration

Question 47

What is the origin of innermost intercostal?

Answer 47

Lower border of ribs

Question 48

What is the insertion of innermost intercostal?

Answer 48

Upper border of rib below rib of origin

Question 49

What innervates innermost intercostal?

Answer 49

Intercostal nerves

Question 50

What is the function of innermost intercostal?

Answer 50

Elevates ribs

Question 51

What is the origin of transversus thoracis?

Answer 51

Internal surface of costal cartilages 2-6

Question 52

What is the insertion of transversus thoracis?

Answer 52

Posterior surface of lower sternum

Question 53

What innervates transversus thoracis?

Answer 53

Intercostal nerves

Question 54

What is the function of transversus thoracis?

Answer 54

Depresses ribs and costal cartilages

Question 55

Which intercostal muscles depress the ribs?

Answer 55

Transversus thoracis and internal intercostal

Question 56

Which intercostal muscles elevate the ribs?

Answer 56

Innermost intercostal and external intercostal

Question 57

What is the orientation of the muscle fibers of external intercostal?

Answer 57

From superior/posterior to inferior/anterior (hands in pockets)

Question 58

What is the orientation of the muscle fibers of internal intercostal?

Answer 58

From inferior/posterior to superior/anterior (praying)

Question 59

What is the orientation of the muscle fibers of the innermost intercostal?

Answer 59

From superior/anterior to inferior/posterior

Question 60

What is the key muscle of respiration?

Answer 60

Diaphragm

Question 61

What is the origin of diaphragm?

Answer 61

Xiphoid process, lower 6 costal cartilages, L1-L3

Question 62

What is the insertion of diaphragm?

Answer 62

Converge into central tendon

Question 63

What innervates diaphragm?

Answer 63

Phrenic nerve

Question 64

What is the function of diaphragm?

Answer 64

Draws central tendon down and forward during inspiration

Question 65

Where do the inferior vena cava, esophagus, and aorta pass through the diaphragm?

Answer 65

Inferior vena cava: T8 Esophagus: T10 Aorta: T12 I ate ten eggs at noon (I:8, 10:E, A:12)

Question 66

During inspiration, what happens to the vertical diameter of the thoracic cage?

Answer 66

Increases as the diaphragm descends

Question 67

During expiration, what happens to the vertical diameter of the thoracic cage?

Answer 67

Decreases to original size as diaphragm descends

Question 68

When the intercostal muscles contract, what happens to the transverse diameter of the thoracic cage?

Answer 68

Increases slightly (bucket handle motion)

Question 69

The movement of ribs 2-6 at the costovertebral joints about an axis going through the neck of the ribs causes the sternal ends of the ribs to rise, changing the ___ diameter.

Answer 69

Anteroposterior (pump handle motion)

Question 70

What three things lay within the costal groove of each rib?

Answer 70

Intercostal vein, artery, and nerve (in that order)

Question 71

The posterior wall of the thorax is supplied by posterior intercostals which are branches of the ___ and ___.

Answer 71

Aorta; costocervical trunk

Question 72

The anterior wall of the thorax is supplied by anterior intercostals which are branches of the ___ and ___ arteries.

Answer 72

Internal thoracic; musculophrenic

Question 73

The intercostal veins drain into what two veins?

Answer 73

Azygos and hemiazygos veins

Question 74

Intercostal muscles are innervated by ___ of thoracic nerves (intercostal nerves).

Answer 74

Ventral rami

Question 75

What dermatome is found at the level of the clavicles and jugular notch?

Answer 75

C4

Question 76

What dermatome is found at the level of the sternal angle?

Answer 76

T2

Question 77

What dermatome is found at the level of the nipples?

Answer 77

T4

Question 78

What are the three basic subdivisions of the thoracic cavity?

Answer 78

1. Pleural cavities (2) 2. Lungs (2) 3. Mediastinum

Question 79

The pleural cavities surround but do not contain the ___.

Answer 79

Lungs

Question 80

The lungs are suspended by roots from the ___ and ___, and are surrounded by pleural cavities.

Answer 80

Trachea; pulmonary vessels

Question 81

What is the thick middle partition in the thorax?

Answer 81

Mediastinum

Question 82

What lines the mediastinum?

Answer 82

Mediastinal pleura

Question 83

What are the boundaries of the thoracic mediastinum?

Answer 83

``` Lateral: two pleural sacs (lungs) Superior: superior thoracic aperture Inferior: diaphragm Anterior: sternum and costal cartilage Posterior: thoracic vertebral bodies ```

Question 84

What are the two parts of the thoracic mediastinum?

Answer 84

1. Superior mediastinum | 2. Inferior mediastinum

Question 85

The superior mediastinum is found superior to the manubriosternal junction (sternal angle) and ___ but inferior to the ___.

Answer 85

T4-T5 IV discs; thoracic inlet

Question 86

The inferior mediastinum is inferior to the ___ but superior to the ___.

Answer 86

Sternal angle; diaphragm

Question 87

What are the three further divisions of the inferior mediastinum?

Answer 87

Anterior, middle, and posterior

Question 88

What is contained within the superior mediastinum?

Answer 88

Thymus, brachiocephalic veins/superior vena cava (left and right), phrenic and vagus nerves, aortic arch and branches (brachiocephalic trunk, left common carotid artery, left subclavian artery), trachea, esophagus, recurrent laryngeal nerve, thoracic duct

Question 89

What is contained within the anterior mediastinum?

Answer 89

Lower portion of thymus, sternopericardial ligaments, loose connective tissue, fat, lymphatic vessels and their nodes, branches of internal thoracic vessels

Question 90

What is contained within the middle mediastinum?

Answer 90

Pericardial cavity/heart, great vessels (ascending aorta, pulmonary arterial trunk, right/left superior and inferior pulmonary veins, inferior portion of superior vena cava, attaching portion of the azygos vein to the SVC), phrenic nerve, roots of lungs

Question 91

What is contained within the posterior mediastinum?

Answer 91

Esophagus, descending aorta/branches, azygos veins, thoracic duct, sympathetic chain, splanchnic nerves

Question 92

What are the boundaries of the anterior mediastinum?

Answer 92

Anterior: sternum Posterior: pericardium