Thorax

Question 1

What are the functions of the thorax?

Answer 1

Protection of vital organs
Assist in respiration
Attachment of muscles
Assist with posture

Question 2

The thorax has an osseocartilaginous framework, what does this mean?

Answer 2

The framework of the thorax is comprised of bone (ribs) and cartilage (intercostal muscles)

Question 3

What vital organs is the thorax protecting?

Answer 3

Heart
Major vessels
Lungs

Question 4

How does the thorax assist in respiration?

Answer 4

The ribcage moves in an out to alter the air pressure inside the lungs relative to the environment

Question 5

What are the three parts of the sternum, from superior to posterior:

Answer 5

1. Manubrium
2. Body
3. Xiphoid Process

Question 6

Where is the clavicular notch and what is its significance?

Answer 6

The notch is on the superior part of the manubrium, it is where the clavicle unites with the sternum

Question 7

When viewing the sternum laterally, there are small depressions in the bone, what are these notches?

Answer 7

They are where the costal cartilage unite with the sternum, (there are 7 of these notches)

Question 8

What is the name for the most inferior part of the sternum?

Answer 8

Xiphoid process

Question 9

What determines the shape of a rib bone?

Answer 9

Its position in the thoracic cage

Question 10

How does the shape of a rib bone change as they go down the thoracic cage?

Answer 10

The 1st rib is shorter and more curved, they then get longer and less sharply curved all the way to the 8th rib, then become shorter again at the bottom to the 12th rib

Question 11

The ribs articulate posteriorly with the ___?

Answer 11

Vertebral body

Question 12

The ribs articulate anteriorly with the ___?

Answer 12

Costal cartilage

Question 13

Describe the structure of a rib bone:

Answer 13

Size and curve depends on position in cage.
Anterior end - cup shaped depression
Shaft - twisted on long axis
Posterior end - 2 demi-facet heads, neck and tubercle

Question 14

What are the different types of thoracic vertebrae?

Answer 14

Typical and Atypical

Question 15

What is meant by a Typical thoracic vertebrae?

Answer 15

Vertebrae T2 - T8

Articular facets on the upper and lower borders of body with a facet on transverse process reciprocally curved

Question 16

What is meant by an Atypical thoracic vertebrae?

Answer 16

T1 = 2 facets on body and one on transverse process
T9 - T12 = only 1 body facet
T11 - T12 = no facet on transverse process

Question 17

What different joints are present at the Thorax?

Answer 17

Manubriosternal
Xiphisternal
Sternocostal
Costochondral
Interchondral
Costotransverse
Costovertebral

Question 18

What are sternocostal joints?

Answer 18

Joints between the costal cartilage and sternum

Question 19

What are costochondral joints?

Answer 19

Joints between the costal cartilage and the ribs

Question 20

What are xiphisternal joints?

Answer 20

Joint between the xiphoid process and the sternal body

Question 21

What are manubriosternal joints?

Answer 21

Joint between the manubrium and the sternal body

Question 22

What are interchondral joints?

Answer 22

Joints between the costal cartilage

Question 23

What are costotransverse joints?

Answer 23

Joint between rib facet and transverse process

Question 24

What are costovertebral joints?

Answer 24

Joints that connect the ribs to the vertebral column

Question 25

What type of joint is the manubriosternal joint and describe the amount of movement present?

Answer 25

A fibrous joint, more specifically symphysis. There is a small amount of angular movement as the joint is hinge-like.

Question 26

Which joints are located posteriorly at the thorax?

Answer 26

Costotransverse | Costovertebral

Question 27

What type of joint is the costotransverse joint and describe the amount of movement present?

Answer 27

Synovial plane | Gliding, and upper ribs can rotate

Question 28

What type of joint is the costovertebral joint and describe the amount of movement present?

Answer 28

Synovial plane | Gliding occurs

Question 29

Which muscle divides the thorax from the abdomen?

Answer 29

The diaphragm

Question 30

Describe the attachment of the diaphragm muscle:

Answer 30

It attaches to the inside of the thoracic cage at 3 main points and attaches in the middle to a fibrous central tendon

Question 31

There are three openings in the middle of the diaphragm muscle, why are these here?

Answer 31

To allow substances to flow through, one hole is for the vena cava, one for the aorta and another for oesophagus

Question 32

The diaphragm is a special muscle as it only has attachment to one bone. On this bone the diaphragm muscle attaches at 3 main points, where are these?

Answer 32

Sternal – posterior aspect xiphoid process Costal– internal surfaces of CC and lower 6 ribs Lumbar – (R) and (L) crura, and arcuate ligaments

Question 33

What is the nerve supply for the diaphragm?

Answer 33

The phrenic nerve (C3, C4, C5)

Question 34

.

Answer 34

.

Question 35

.

Answer 35

.

Question 36

What limits the contraction distance of the diaphragm?

Answer 36

The abdominal contents

Question 37

What are the 3 layers of the intercostal muscles?

Answer 37

External Intercostals Internal Intercostals Innermost Intercostals

Question 38

What direction are the muscle fibres travelling in the external intercostals?

Answer 38

Fibres down and medial

Question 39

What direction are the muscle fibres travelling in the internal intercostals?

Answer 39

Fibres down and back

Question 40

What direction are the muscle fibres travelling in the innermost intercostals?

Answer 40

Fibres down and back

Question 41

When are external intercostals used?

Answer 41

Inspiration to elevate the ribs

Question 42

When are internal intercostals used?

Answer 42

Expiration to lower the ribs (although there is debate about this)

Question 43

What are in the neurovascular bundle beneath the internal intercostals?

Answer 43

Nerves, Veins and Artery

Question 44

Where is the parietal pleura located?

Answer 44

Behind the innermost intercostals

Question 45

Which muscles are responsible for keeping the intercostal spaces rigid?

Answer 45

Intercostal muscles

Question 46

(In relation to air pressures) How does the thoracic cavity leads expiration?

Answer 46

Volume in thoracic cavity decreases, Therefore air pressure increases Air rushes out of the lungs as pressure inside the lungs > outside the lungs

Question 47

What are the different mechanisms which work to alter the volume of the thorax?

Answer 47

Pump handle mechanism Bucket handle mechanism Descent of diaphragm

Question 48

What affect does the descent of the diaphragm have on the diameter of the thorax?

Answer 48

Increased vertical diameter Increased transverse diameter Increased anteroposterior (AP) diameter

Question 49

In the ribs, where is the pivot located?

Answer 49

Around the costotransverse joint

Question 50

(In relation to air pressures) How does the thoracic cavity leads inspiration?

Answer 50

Volume in thoracic cavity increases, Therefore air pressure decreases Air rushes into the lungs as pressure inside the lungs < outside the lungs

Question 51

What significance does the pivot system of the ribs have?

Answer 51

The pivot is posterior so any posterior movement will be amplified at the front.

Question 52

Explain the pump handle mechanism:

Answer 52

Rotation backwards of rib neck, elevating the anterior end of rib, causes a hinge effect at manubriosternal joint which increases the AP diameter

Question 53

Explain the buckle handle mechanism:

Answer 53

Rib pivots around anterior and posterior ends, lower border of rib raised and everts, increasing transverse diameter of throat

Question 54

Which muscles are involved in quiet (resting) respiration?

Answer 54

Primarily diaphragm, scalenes fix 1st rib

Question 55

Which muscles are involved in deep inspiration?

Answer 55

Diaphragm, intercostal muscles, scalenes (1st rib), quadratus lumborum (12th rib)

Question 56

Which muscles are involved in expiration?

Answer 56

Passive movement relies on the recoil of lungs

Question 57

Which muscles are involved in forced expiration?

Answer 57

Abdominal muscles and Latissimus dorsi

Question 58

What structures pass through/behind the diaphragm. Why is it necessary for the structure to pass behind the diaphragm?

Answer 58

Aorta behind so movement of the diaphragm does not compress the vessel (T12) Oesophagus at T10 through right crura Vena Cava at T8, central tendon

Question 59

Name the accessory muscles of respiration how do they help with breathing?

Answer 59

Scalenes/Sternocleidomastoid – increase Vertical diameter of thorax

Question 60

Indicate the type of joint, the structures involved, the ligaments and the movement occurring at the Costochondral joints:

Answer 60

Primary cartilaginous (Synchondroses) Articulation between the costal cartilage and the rib Joined by hyaline cartilage No movement

Question 61

Indicate the type of joint, the structures involved, the ligaments and the movement occurring at the Sternocostal joints:

Answer 61

``` Primary cartilaginous (Synchondroses) Articulation between the costal cartilage and the sternum, capsule, anterior and posterior radiate ligaments Bones connected by hyaline cartilage Rest are synovial plane 1st no movement, 2 -7 slight gliding ```

Question 62

Indicate the type of joint, the structures involved, the ligaments and the movement occurring at the Manubriosternal joints:

Answer 62

Secondary cartilaginous (Symphysis) Articulating bones Manubrium and Sternal body Ends of bone covered with hyaline cartilage and joined by fibrocartilage, slight hinge like movement

Question 63

Indicate the type of joint, the structures involved, the ligaments and the movement occurring at the 4th Costotransverse joint:

Answer 63

Synovial plane joint, articular facet on the corresponding transverse process (T4) and article facet on tubercle of the rib, capsule, lateral costotransverse ligament, costotransverse ligament and superior costotransverse ligament, rotation due to reciprocal curvature of articular surfaces

Question 64

During normal and deep breathing which diameters of the thorax are increased?

Answer 64

Normal, quite breathing, vertical diameter increased | Deep breathing, vertical, anterior/posterior and transverse

Question 65

What are accessory muscles?

Answer 65

Muscles other than the diaphragm and intercostals that help with breathing.