HS2-14 Thoracic Wall and Diaphragm

Question 1

How many thoracic vertebrae are there?

Answer 1

12

Question 2

What is a distinguishing feature of thoracic vertebrae?

Answer 2

articular facets for ribs

Question 3

What is the costal cartilage?

Answer 3

anterior end of rib

Question 4

What is the costal margin?

Answer 4

upturned cartilages of ribs 8-10, connected to costal cartilage of rib 7

Question 5

What are the two systems to classify ribs?

Answer 5

true-false-floating

typical-atypical

Question 6

Describe the true-false-floating system of classifying ribs.

Answer 6

true = ribs 1-7 with direct articulation to sternum via costal cartilage

false = ribs 8-10 that articulate w/ sternum via costal margin

floating = ribs 11 and 12, w/ no attachment to sternum

Question 7

Describe the typical-atypical of classifying ribs.

Answer 7

typical = ribs 3-9

atypical = ribs 1, 2, 10, 11, 12

Question 8

What are the “typical” features of a rib (for the purposes of classification)? (4)

Answer 8

head

neck

tubercle

shaft

Question 9

What is the costal groove?

Answer 9

depression on inferior border of rib

Question 10

What structures are found in the costal groove? (2)

Answer 10

intercostal nerve

intercostal vessels

Question 11

The body of the sternum articulates with which ribs?

Answer 11

ribs 3-6

Question 12

What is the sternal angle of the sternum?

Answer 12

junction of manubrium and body

Question 13

The sternal angle articulates with which ribs?

Answer 13

articulates with rib 2

Question 14

What is the xiphisternal junction?

Answer 14

junction of body of sternum and xiphoid process

Question 15

The xiphisternal junction articulates with which ribs?

Answer 15

rib 7

Question 16

Describe the structure of the costovertebral joint.

Answer 16

head of rib articulates with bodies of 2 vertebrae: one at the same level as rib, and then the vertebrae above it

Question 17

Describe the structure of the costotransverse joint.

Answer 17

tubercle of rib articulates with transverse process of vertebrae on same level

Question 18

What is another name for the thoracic inlet?

Answer 18

superior thoracic aperture

Question 19

What are the boundaries of the thoracic inlet?

Answer 19

vertebral body of T1

first ribs

manubrium

Question 20

What is another name for the thoracic outlet?

Answer 20

inferior thoracic aperture

Question 21

What are the boundaries of the thoracic outlet? (4)

Answer 21

T12

rib 12

costal margins

xiphisternal joint

Question 22

What are the three layers of intercostal muscles?

Answer 22

external (most superficial)

internal

innermost

Question 23

What are the boundaries of the external intercostal muscle?

Answer 23

tubercle of rib → midclavicular line

Question 24

What is a visual characteristic of the external intercostal muscle?

Answer 24

“hands-in-pocket” fiber orientation

Question 25

What happens to the external intercostal muscles as they approach the anterior aspect of the ribs?

Answer 25

become membranous

Question 26

What are the boundaries of the internal intercostal muscles?

Answer 26

sternum → midaxillary line

Question 27

What is the orientation of the internal intercostal muscles?

Answer 27

at right angle to those of external intercostal muscles

Question 28

What happens to the internal intercostal muscles as they approach the posterior aspect of the ribs?

Answer 28

become membranous

Question 29

What is the orientation of the innermost intercostal muscles?

Answer 29

same as internal intercostal muscle (so bsaically perpendicular to the external intercostal muscles)

Question 30

Where are the innermost intercostal muscles membranous?

Answer 30

anteriorly AND posteriorly

Question 31

The transversus thoracis consists of

Answer 31

several muscular slips running from sternum to 2nd-6th costal cartilages

Question 32

Where are the subcostal muscles found?

Answer 32

posteriorly at the same level as the innermost intercostals span more than one intercostal space

Question 33

What are the three accessory muscles of respiration?

Answer 33

pectoralis major/minor serratus anterior scalene muscles

Question 34

What is the origin of the intercostal nerves?

Answer 34

ventral rami of the first 11 thoracic spinal nerves

Question 35

What is the origin of the subcostal nerve?

Answer 35

ventral ramus of 12th thoracic spinal nerve

Question 36

What provides innervation to the intercostal muscles?

Answer 36

intercostal nerves

Question 37

What provides innervation to the transversus thoracis?

Answer 37

intercostal nerves

Question 38

What provides innervation to the subcostal muscles?

Answer 38

intercostal nerves

Question 39

What innervates the superior and inferior serratus posterior?

Answer 39

intercostal nerves

Question 40

Where do the intercostal nerves provide sensory innervation? (4)

Answer 40

lateral and anterior thorax abdominal wall parietal pleura parietal peritoneum

Question 41

What are the primary arteries of the thoracic wall? (2)

Answer 41

paired internal thoracic artery paired intercostal arteries

Question 42

The internal thoracic artery is a branch of

Answer 42

the subclavian artery

Question 43

Describe the position of the internal thoracic artery relative to the sternum.

Answer 43

internal thoracic artery runs _lateral_ to the sternum

Question 44

What holds the internal thoracic artery against the ribs?

Answer 44

transversus thoracis muscle

Question 45

In the thorax, the internal thoracic artery bifurcates into

Answer 45

musculophrenic artery + superior epigastric artery

Question 46

Describe the anterior arterial supply of the thoracic wall.

Answer 46

ribs 1-6 = arterial supply from internal thoracic artery ribs 7-9 = arterial supply from musculophrenic artery ribs 10-11 = absent

Question 47

Describe the posterior arterial supply of the thoracic wall.

Answer 47

ribs 1-2 = arterial supply from indirect branches of subclavian artery ribs 3-11 = arterial supply from descending aorta

Question 48

What are the primary veins of the thoracic wall?

Answer 48

paired internal thoracic veins paired intercostal veins

Question 49

Describe the venous drainage of the anterior aspect of the thoracic wall.

Answer 49

drain into internal thoracic vein + musculophrenic vein

Question 50

Describe the venous drainage of the posterior aspect of the thoracic wall. (2)

Answer 50

right intercostal vein drains into azygos vein left intercostal vein drains into hemiazygos vein

Question 51

The intercostal neurovascular bundle is found in what thoracic wall structure?

Answer 51

intercostal groove

Question 52

What is the order of the structures found in the intercostal neurovascular bundle?

Answer 52

vein artery nerve [VAN]

Question 53

The intercostal neurovascular bundle is found between what two muscle layers?

Answer 53

innermost and internal intercostal muscle layers

Question 54

What is the chief muscle of respiration?

Answer 54

diaphragm

Question 55

What is the anatomical function of the diaphragm?

Answer 55

separates thoracic and abdominal cavity

Question 56

What are the components of the diaphragm?

Answer 56

central tendon + 3 muscular parts (sternal, costal, lumbar)

Question 57

What are the three major openings of the diaphragm?

Answer 57

vena caval foramen esophageal hiatus aortic hiatus

Question 58

Describe the vena caval foramen. (2)

Answer 58

at T8 opens into inferior vena cava

Question 59

Describe the esophageal hiatus. (2)

Answer 59

at T10 opens into esophagus and vagal trunks

Question 60

Describe the aortic hiatus. (2)

Answer 60

at T12 opens into descending aorta, thoracic duct, and azygos vein

Question 61

What is the arterial supply to the diaphragm? (3)

Answer 61

pericardiacophrenic arteries musculophrenic arteries inferior phrenic arteries

Question 62

What innervates the diaphragm?

Answer 62

phrenic nerve

Question 63

Differentiate between the right and left hemidiaphragms in a frontal chest radiograph.

Answer 63

right hemidiaphragm is higher than left by 1-2 cm

Question 64

What kind of joint is the costosternal joint? (2)

Answer 64

1st costosternal joint is cartilaginous all other costosternal joints are synovial

Question 65

The periocardiacophrenic artery is a branch of

Answer 65

the internal thoracic artery

Question 66

Where is the neurovascular bundle located relative to its rib?

Answer 66

the neurovascular bundle is located _below_ its associated rib