Thorax 2 Flashcards
(79 cards)
1
Q
What is the thoracic skeleton composed of?
A
- 12 thoracic vertebrae
- 12 pair of ribs + costal cartilages
- Sternum
2
Q
What does the costal cartilages articulate with?
A
- Articulate at the back with the vertebrae
- Articulate with sternum at the front
3
Q
Describe the thoracic vertebrae
A
- 12 in number
- T1 to T12
- Heart shaped vertebral body
- Facets on the body for articulations with heads of ribs
- Facets on the transverse process for articulations with the tubercles of the ribs EXCEPT for ribs 11 & 12
4
Q
Label the diagram
A
5
Q
What is the vertebral foramen?
A
- The centre carries the spinal cord + the meningeal layers
6
Q
Label this diagram
A
7
Q
How many ribs are there?
A
-12 pairs of ribs
8
Q
What are true ribs?
A
- The first seven ribs reach the sternum -> articulate with the sternum via their own costal cartilage
9
Q
What are false ribs?
A
- Ribs 8,9 and 10 reach the sternum via the costal cartilage of the rib above
- These are false ribs
10
Q
What are floating ribs?
A
- Ribs 11 and 12 lack an anterior attachment completely
- Ribs articulate at the posterior surface with a thoracic vertebrae
11
Q
What do the different parts of the rib do?
A
- The head articulates with the body of the vertebral body
- The tubercle articulates with the facet on transverse process
- The costal cartilage which attaches rib to sternum
12
Q
What is the outline of the costal margin?
A
Where the diaphagm attaches to the chest wall
13
Q
Label the diagram
A
14
Q
Where do the ribs attach to the sternum?
A
1st costal cartilages attach to manubrium
2nd to manubriosternal joint (joint between manubrium and sternum)
3-7th ribs attach directly to body of sternum
8th-10th ribs attach to sternum via costal cartilages of the rib above
11th and 12th have no anterior attachment to sternum -> floating ribs
15
Q
What is the thoracic inlet?
A
- Superior thoracic aperture
- Ring formed from the first thoracic vertebra posterior, the first ribs and the manubirum
- Conduit for structures passing from head + neck into thorax and abdominal cavity e.g oesophagus & trachea
- Conduit for vessels going to and from the heart
16
Q
What vessels go to and from the heart inside the thoracic inlet?
A
- Internal jugular vein
- Subclavian veins
- Subclavian arteries (posterior to the above)
- Common carotid arteries (posterior to the above )
17
Q
Label this diagram
A
18
Q
Describe the appearance of the diaphragm
A
- Has a flat, central tendon with muscle radiating out to the costal margin + the vertebrae
19
Q
Label the diagram
A
20
Q
How does the diaphragm increase chest volume during breathing?
A
- Dome flattens to increase the vertical diameter of the chest
- Pulls the costal margin up to increase both the transverse + anteroposterior diameters
21
Q
What do the intercostal muscles?
A
- They sit in between adjacent ribs
- Help to stiffen the chest wall and to improve the efficiency of breathing movements
22
Q
What does elevation and depression of the diaphragm lead to?
A
They significantly alter the vertical dimensions of the thorax
Depression results when the muscle fibers of the diaphragm contract
Elevation occurs when the diaphragm relaxes
23
Q
How do the sternum and the ribs move to increase the chest volume?
A
- Sternum moves anteriorly + superiorly increase anteroposterior dimension of the chest
- Ribs move in a bucket handle type movement where they elevate and increase the media-lateral dimensions of the chest
24
Q
How are the intercostal muscles arranged?
A
- The intercostal muscles occupy the intercostal muscles
- Organised into 3 layers 90 degree to each other
25
What are the 3 intercostal muscles?
▪
The external intercostal muscles are the most superficial.
▪
The internal intercostal muscles are sandwiched between the external and innermost muscles.
▪
The innermost intercostal muscles are the deepest of the three muscles.
26
How are external intercostals arranged?
- 11 pairs of external intercostal muscles extend from inferior margins of the ribs above to the superior margins of the ribs below
- The muscles extend around the thoracic wall from the regions of the tubercles of the ribs to the costal cartilages, where each layer continues as a thin connective tissue aponeurosis termed the external intercostal membrane .
- EIM most active in inspiration
27
How are the internal intercostal muscles arranged?
- 11 pairs of IIM
- Attachments begin anteriorly at the sternum from lower border or rib above to the rib below
- Their fibers are at right angles to the external intercostals
This layer continues medially toward the vertebral column, in each intercostal space, as the internal intercostal membrane (IIM are replaced by membrane posteriorly
28
How are the innermost intercostal muscles arranged?
- Deep to the internal intercostal muscles
- Orientated in the same direction as IIM
- They **extend between the inner surfaces of adjacent ribs from the medial edge of the costal groove to the deep surface of the rib below**. Importantly, the **neurovascular bundles** associated with the intercostal spaces pass around the **thoracic wall in the costal grooves** in a plane between the innermost and internal intercostal muscles.
29
Label the diagram
30
What innervates the muscles of the intercostal spaces and the skin overlying the intercostal spaces?
Intercostal nerves
31
How many pairs of intercostal nerves are there?
11 pairs of intercostal nerves + 1 sub costal nerve below the 12 ribs -\> anterior primary rami of first 11 thoracic spinal nerves
- mixed nerves -\> motor and sensory components
32
What are the cutaenous branches of the intercostal nerves?
- they supply the skin overlying the intercostal spaces
- there are laternal cutaneous branches -\> divides into anterior and posterior branches
- anterior cutaneous branch -\> divides into medial + lateral branch
33
What do the motor components of the intercost nerve do?
- innervate and provide the intercostal muscles with motor innervation to enable contraction
34
Describe the arterial supply of the intercostal spaces
- intercostal spaces have arterial supply from branches of descending aorta + internal thoracic arteries
- intercostal arteries enter the 1st - 9th intercostal spaces both anteriorly and posteriorly
- arteries supplying posterior part = posterior intercostal arteries (mostly direct branches from descending thoracic aorta
- anterior aspect of each intercostal space = anterior intercostal arteries
35
What type of artery do you get in:
- upper 6 intercostal spaces
- 7th - 9th intercostal spaces
- 10th and 11th intercostal spaces
- upper 6 intercostal spaces -\> branches of internal thoracic artery
- 7th - 9th intercostal spaces -\> branches of one of the two terminal branches of internal thoracic artery, musculophrenic artery (L + R)
- 10th and 11th intercostal spaces -\> only suppled by posterior intercostal arteries
36
How does venous drainage occur from intercostal space?
- via anterior + posterior branches that drain back into heart via azygous vein or internal thoracic veins
37
What are the neurovascular bundles of the intercostal space?
- they run in superior aspect of intercostal space
## Footnote
Vein, artery & nerve run just below rib deep to internal intercostal muscles – closer together than shown -\> in the costal groove
38
What area is safe to insert a chest drain and above what should the drain be inserted?
- Anterior border of latissimus dorsi
- Lateral border of the pectoralis major muscle
- Inferior border is a line that's superior to the horizontal level of the nipple
- Superior border is below the apex of the axilla.
drain should be inserted on superior surface of rib to avoid damage to neurovascular bundle
39
Where does the trachea extend inferiorly from and from what vertebral levels?
- inferiorly from laryngeal cartilages
- from C6-T4/5
40
What is the trachea held open by?
- C-shaped cartilaginous rings which are open posteriorly
41
What is the name of the lowest cartilaginous ring?
- carina -\> has a hook, resembles keel of ship
42
What does the trachea do at vertebral level T4/5?
Trachea bifurcates into principal left bronchus and a principal right bronchus
43
Which bronchus is wider and more vertical -\> why is this relevant?
- Right main bronchus is wider + more vertical than the left
- inhaled objects can often descend into right main bronchus + into lung, instead of left
44
What does the main bronchus divide into and what do these supply?
- Lobar/secondary bronchi -\> supply the lobes of the lungs
45
What do the lobar bronchi divide into further + what do these supply?
- They divide further into segmental/tertiary bronchi -\> these supply the bronchopulmonary segments
46
What are the bronchopulmonary segments + how many are there?
- smallest functionally independent regions of the lungs
- there are ten on each side
47
How high up does the apex of the lung rise?
- 3-4cm above level of first costal cartilage
48
What does the base of the lung rest on?
- concave + rests on convex surface of diaphragm
49
What are the 3 borders of the lungs?
what are the 3 surfaces of the lungs
anterior, posterior + inferior
costal, medial (mediastinal) + inferior (diaphragmatic)
50
What does the diaphragm separate the lungs from?
- diaphragm sits inferiorly to lungs
- separates right lung from right lobe of liver
- left lung from left lobe of liver, also stomach + speen
51
What are the general features of the mediastinal surface of the lung: posterior part, anterior part and cardiac impression?
posterior part: in contact with thoracic vertebra
anterior part: deeply concave + accommodates the heart
above + behind cardiac impression: is the hilum
52
What is the hilum of the lung?
- where vessels, bronchi + nerves enter and leave the mediastinum
53
name the highlighted structure
hilum
54
How many lobes does the left lung have?
2 lobes: superior + inferior lobe
55
What fissure separates the 2 lobes of the left lung?
oblique fissure
56
What lobe lies above the oblique fissure and what lobe lies below the oblique fissure?
- superior lobe lies above the fissure
- inferior lobe is below the fissure
57
What does the superior lobe of left lung contain?
- apex of the lung and most of the anterior part of the lung
58
What does the inferior lobe of the left lung contain?
- contains the most posterior part of the lung
59
How many lobes does the right lung have?
3 lobes: superior, middle and inferior lobes
60
What are the 3 lobes of the right lungs separated by?
- 2 fissures -\> oblique fissure and horizontal fissure
61
What does the oblique fissure separate in the right lung?
What does the horizontal fissure separate?
- separates the infeiror lobe from the other 2 lobes
- horizontal separate superior from middle lobe
62
What does the root of the lung connext and what is it formed by?
- connects the mediastinal surface to the heart and the trachea
- formed by structures that leave the hilum
63
what are the structures that leave the hilum that form the root of the lung?
- pulmonary artery -\> takes deoxygenated blood from right ventricle
- 2 pulmonary veins -\> return deoxygenated blood to left atrium
- bronchial arteries -\> transport oxygenated blood from descending aorta + veins
- autonomic nerves
- lymph vessels
- nodes
64
What are the structures located in the hilum and within each root?
a pulmonary artery
two pulmonary veins
a main bronchus
bronchial vessels
nerves
lymphatics
65
Label this diagram
66
What vessels form the superior vena cava?
- Union of left and right brachiocephalic veins
67
What vein drains the posterior wall of the chest?
azygous vein
68
Label this diagram
69
What is the pleura?
- think layer of flattened cells that line each of the pleural cavities and covers the outside surface of the lungs
- composed of 2 layers
70
1) What is the layer of pleura closest to the lung surface?
2) what is the layer of the pleura closest to the inner surface of the chest wall?
1) visceral pleura
2) parietal pleura
71
How does inhaling occur once the chest is expanded due to diaphragm and rib movements?
- pleural cavity is also expanded
- elastic lungs expand within pleural cavity and resulting negative pressure causes air to be sucked into trachea + bronchi and down into lungs
72
What is quiet expiration?
- passive activity not requiring muscle contraction -\> depends upon elastic recoil in tissue throughout the lungs in the ribcage
73
what happens during deep or forced expiration?
assisted by muscles of abdominal wall that squeeze the abdominal organs against the diaphragm
pulls the lower ribs downwards
74
What nerve delivers motor commands to the diaphragm?
phrenic nerve from spinal cord segments C3, C4 and C5
75
What happens when motor commands are delivered by phrenic nerve to diaphragm?
what happens after this?
phrenic nerve from spinal cords C3, C4 and C5 -\> vertical dimension of thoracic cavity is increased
diaphragm passes on abdominal organs which intially descend due to abdominal wall relation during inspiration
further descent is stopped by abdominal viscera -\> more diaphragm contraction raises the costal margin upwards
increased thoracic cavity produced by diaphragm and rib movements causes inspiration, reduces intrapleural pressure + entry of air through respiratory passages
76
Vertebral levels for:
vena cava
oesophagus
aorta
vena cava -\> T8 (with phrenic nerve)
oesophagus -\> T10
aorta -\> T12 (along with thoracic duct + azygous vein)
77
label this diagram
78
What is the diaphragm attached to?
- the costal margin (lower border of rib cage)
- xiphoid process
- ends of floating ribs 11 and 12
- posteriorly to lumbar vertebrae
79
What abdominal organs are covered by the dome of the diaphragm bulging high up inside the rib cage?
- liver
- pleura
- lung
- rib cage
