Thorax Flashcards
(90 cards)
1
Q
What is the function of the thorax?
A
• Protection (of the heart, great vessels, lungs, major airways, liver, stomach, spleen, kidneys)
• Provides rigidity and elasticity (essential in respiration)
• Provides attachment for muscles for locomotion
• Haematopoiesis
• In respiration:
- Resists a negative intrathoracic pressure
- Works in partnership along with the diaphragm and abdominal muscles
• Connections with the upper neck and upper limbs and abdomen
2
Q
Describe the shape of the thorax
A
- Shape of a truncated cone
* Transverse diameter is greater than the sagittal diameter
3
Q
What constitutes the thoracic cage?
A
- Sternum
- 12 pairs of ribs
- Costal cartilage
- 12 thoracic vertebrae
- Intervertebral discs
4
Q
What constitutes the thoracic wall?
A
- Thoracic cage
- Skin
- Subcutaneous tissue
- Thoracic muscles and fascia
- 3 layers of muscles extending between the ribs i.e. intercostal space
- Mammary glands/breast tissue in females
5
Q
Describe the position of articular processes in the thoracic vertebrae
A
Vertical
6
Q
Describe the position of articular facets in the thoracic vertebrae and describe the effect this has on movement
A
- Facets face slightly medially
* Allows some rotation but no flexion
7
Q
Which part of the rib is more transverse?
A
Posterior part
8
Q
What is the function of costal cartilage of the ribs?
A
Mobility and elasticity
9
Q
Which ribs are classed as true ribs and what are they?
A
- Ribs 1-7
* Attached directly to the sternum through costal cartilage
10
Q
Which ribs are classified as false ribs and what are they?
A
- Ribs 8-10
* Attach indirectly to the sternum through the costal cartilage of the 7th rib
11
Q
Which ribs are classified as floating ribs and what are they?
A
- Ribs 11-12
* They do not articulate with the sternum
12
Q
Which ribs are typical ribs?
A
• Ribs 2-9 ( sometimes 10)
13
Q
What are the features of typical ribs?
A
- Head
- Neck
- Tubercle
- Body
- Costal angle
- Costal groove
14
Q
What is the significance of the costal angle?
A
It is where the deep back muscles attach
15
Q
How is the first rib atypical?
A
- It has a scalene tubercle where the anterior scalene muscle attaches
- It has a groove for the subclavian artery
- It has a groove for the subclavian vein
- It has a single facet on the head to articulate with the T1 vertebra only (others have 2)
- It doesn’t have a costal groove
16
Q
Which ribs are atypical?
A
- 1
- 2
- 10
- 11
- 12
17
Q
What is atypical about the second rib?
A
• It has tuberosity for serratus anterior
18
Q
How is the 10th rib atypical?
A
It only has one facet for articulation with its numerically corresponding vertebrae
19
Q
How are the 11th and 12th ribs atypical?
A
- They have no neck
* One facet for articulation with their corresponding vertebrae
20
Q
What are the parts of the sternum?
A
• Manubrium
(• Sternomanubrium joint between manubrium and body)
• Body
• Xiphoid process (xiphisternum)
21
Q
What is the level of the sternal angle?
A
- Intervertebral disc between T4 and T5
- Where the 2nd costal cartilage attaches to the sternum
- Proximal and distal boundaries of the aortic arch
- The bifurcation of the trachea
- Superior limit of the pulmonary trunk
22
Q
Where is the solar plexus region?
A
T6 (T6 dermatome = xiphisternum)
23
Q
Where is a site of bone marrow aspiration?
A
The sternum
24
Q
Describe the costovertebral joint
A
- Each rib articulates with the superior costal facet of its corresponding vertebra and the inferior costal facet of the vertebra above (except 1, 11 and 12)
- Synovial joint, supported by a capsule with ligaments
25
Which vertebra is involved in only 1/2 a costovertebral joint?
T10
26
Which vertebra is involved in 1 and 1/2 costovertebral joints?
T1
27
Which vertebrae have 2 costal facets?
T2-T9
28
Which vertebrae have 1 costal facet?
* T11
| * T12
29
What is the costotransverse joint?
• Joint between the tubercle of the rib (except 11 and 12) and the transverse process of its corresponding vertebra
30
What is the difference between the costotransverse joints 1-7 and 8-10?
* 1-7: Curved facets allowing rotatory movement
| * 8-10 have flat facets allowing gliding
31
How do the ribs articulate with the costal cartilage?
Primary cartilaginous (hyaline) joint
32
Describe the position of the costal cartilages of ribs 1-4 and ribs 5-10
* 1-4: horizontal
| * 5-10 increasingly oblique
33
What are the boundaries of the thoracic inlet (superior aperture)?
* T1 vertebra
* 1st rib
* Costal cartilage
* Manubrium
34
Describe the position of the thoracic inlet
• Slopes antero-inferiorly to the level of T2/3 from the transverse plane
35
What structures pass between the thorax and the upper limbs and the first rib?
* Subclavian vein
* Subclavian artery
* Inferior trunk of the brachial plexus
36
What are the boundaries of the thoracic outlet?
* T12 vertebra
* 11th and 12th ribs
* Costal cartilages of ribs 7-10 (costal margin, costal arch)
* Xiphoid processs
37
What is thoracic outlet syndrome?
• Compression of nerves and vessels between bones
• Brachial plexus, subclavian artery, subclavian vein
• Upper surface of the first rib and the inferior surface of the clavicle as they enter the upper limb
• 3 Places:
- First rib and the clavicle
- Scalene triangle
- coracoid process and pec. minor
38
What are the stages of breasts?
* Pre-pubertal
* Post pubertal
* After pregnancy
39
What are the breasts?
* Accessory gland consisting of mammary glands, skin and connective tissues
* Modified sweat glands
* Similar structure in males and pre pubertal females
40
What are Montgomery tubercles?
Visible portions of the areolar glands on the skin surface withins the areola
41
What are the areolar glands?
Sebaceous glands in the breast
42
Describe the position of the breasts in adult females
* Between the 2nd and 6th (7th) ribs
* From the lateral border of the sternum to the mid axillary line
* The upper lateral section may extend towards the axilla (axillary tail of spence) (may perforate deep fascia and extend as far superiorly as the apex of the axilla)
* Between the superficial fascia and the muscles in the deep (pectoralis) fascia
43
Which muscles do the breasts sit on?
* Pectoralis major
| * Partially serratus anterior and external oblique muscles
44
What are cooper's ligaments?
* A well developed, connective tissue stoma surrounds the ducts and lobules of the mammary gland
* In certain regions this condenses to form suspensory ligaments of the breast
* Connects the deep fascia to the skin
* Support the breast
45
How many lobes are the in the breast?
• 15-20 comprising lobules and ducts
46
What is peau d'orange
Swelling of the breast tissue with a pitted appearance due to the cooper's ligaments
47
What is the retromammary space?
* Layer of loose connective tissue between the deep layer of superficial and deep fascia
* It provides some degree of movement over underlying structures
* Potential space
48
Breast not moving
* Fixed to pec. major
| * Likely that something has invaded the retromammary space
49
What is the arterial supply to the medial aspect of the breast?
Internal thoracic artery (branch of the subclavian)
50
What is the arterial supply to the lateral aspect of the breast?
* Lateral thoracic and lateral thoracoacromial branches of the axillary artery
* Lateral mammary arteries
* Mammary branch (of the anterior intercostal artery)
* Anterior intercostal arteries
51
Lymph drainage of the areola and lateral quadrants
Axillary lymph nodes
52
Lymph drainage of the medial quadrants
* Parasternal lymph nodes
| * Crosses to opposite breast by crossing the midline
53
Lymph drainage of the inferior quadrants
• Inferior phrenic lymph nodes (which can pass through the diaphragm)
54
How many pairs of intercostal spaces are there?
11
55
What are the 3 layers of muscle in the intercostal space?
* External intercostal
* Internal intercostal
* Innermost intercostal
56
Describe the external intercostal
* From the inferior edge of the rib above to the superior edge of the rib below
* Anteriorly, the muscle fibres are replaced by external intercostal membrane
* Raise the ribs in inspiration and prevents in drawing during inspiration
57
Describe the internal intercostal
* From the lateral edge of the costal groove of the rib above to the the superior edge of the rib below
* Posteriorly, muscle fibres are replaces by internal intercostal membrane
* Prevents in-drawing during respiration
* Aids elastic recoil by moving the ribs inferiorly in expiration
58
Describe innermost intercostal
* Very thin, covers the neurovascualr bundle
* Acts with the internal intercostal muscles
* Deep surface is covered with endo thoracic fascia
59
Transverse thoracis
* Posterior to the sternum
| * Internal aspect of the ribs and costal cartilages 3-6 to sternum, xiphisternum and costal margin
60
Subcostalis
* Lies on the posterior wall
| * Lowers ribs, internal surface, near angle down to the inner surface of 2-3 ribs below
61
Spinal nerve
• Comes out of the vertebra via the intervertebral foramen
62
What are the risks relating to the spinal nerve?
* Risk of compression by arthritis, fracture or disc prolapse
* Osteoporotic fractures (collapse) of the vertebral body and facet joint arthritis may cause local and spinal nerve pain
63
What happens as a spinal nerve exits the vertebra?
They divide into 2:
• Anterior rami- does not form a plexus, maintains its segmental pattern and become intercostal nerves (except T1, T2 and T12)
• Posterior rami
64
Where do the anterior rami of the spinal nerve travel?
On the posterior surface on the inferior border of the ribs
65
What do the intercostal nerves supply?
* Intercostal muscles
| * Skin
66
Describe the branches of the intercostal muscles
Gives off a lateral cutaneous branch then anterior cutaneous branch
67
What happens to the intercostal nerve once it has given off the lateral cutaneous branch?
* Travels anteriorly in the spinal groove
| * Becomes the anterior cutaneous branch when it gets more superficial / parasternally
68
Which nerves supply the thoracic wall?
* Intercostal nerves
| * Supraclavicular nerves (C3-4)
69
Which of the spinal nerves has no cutaneous distribution over the thorax wall?
T1
70
What is the level of the xiphoid process?
T10
71
What is at the level of the sternal angle?
• Second costal cartilage
72
What does the ventral ramus of T1 go on to supply?
* Small muscles of the hand
* Skin on the medial aspect of the arm and forearm
* muscles of the 1st intercostal space
73
What is the arterial supply to the thoracic wall?
• Subclavian artery
- Vertebral artery (supplies head)
- Thyrocervical artery
- Costocervical trunk
- internal thoracic artery - gives off anterior intercostal
• Thoracic aorta
- parietal branches supply wall:
- 3rd-11th posterior intercostal arteries
- subcostal artery (inferior to the 12th rib, suppleies the posterior abdominal wall)
- superior phrenic artery
74
What does the internal thoracic artery terminate as?
Superior epigastric and musculophrenic arteries
75
Describe the posterior intercostal arteries
* 1st and 2nd are from the supreme intercostal branch of costocervical trunk
* 3rd-11th are from the thoracic aorta
* 2 per space
76
Coarctation of the aorta - anastomosis
Anastomosis of the anterior and posterior intercostal arteries form a collateral circulation
77
Describe the anterior intercostal arteries
* From the internal thoracic (mammary) artery
* 2 per space in spaces 1-6
* 7th to 10th anterior intercostal arteries are branches of the musculophrenic artery
* 11th intercostal space and subcostal area don't have one
78
What do the anterior intercostal veins drain to?
The internal thoracic vein to the brachiocephalic vein
79
What do posterior intercostal veins drain to?
Either to the brachiocephalic vein or to the superior vena cava via the azygos system
80
Supply of T2
* Large lateral cutaneous branch (intercostobrachial nerve) that supplies the thorax wall in the axilla and upper medial part of the upper limb
* At risk in breast surgery
81
What does the azygos system drain?
• Posterior part of the thorax and part of the posterior abdominal wall
82
Where does the azygos vein begin?
* Lumbar and subcostal veins
| * and/or direct branch of the inferior vena cava
83
How does the azygos vein enter the thorax?
In the aortic hiatus at T12
84
Describe the position of the azygos vein in the thorax
* Ascends in the posterior mediastinum
* passes posterior to the right lung hilum
* Arches and opens up into the superior vena cava (connects the inferior and superior vena cava)
85
Describe the origin and the route of the hemiazygos vein
* Has connections to the left renal vein
* Passes thorough or behind the left crus of the diaphragm
* Crosses at approx T9 and joins the azygos
86
Describe the route of the accessory hemiazygos
* Descends from the 4th intercostal space
* Crosses to the right at approx T8
* Can open into the azygos, hemiazygos or both
87
Anterior lymph drainage of the thorax
* Parasternal nodes
| * Bronchomediastinal trunks
88
Posterior drainage of the thorax
* Intercostal nodes
| * Thoracic duct (inferiorly) or bronchomediastinal trunks (superiorly)
89
where do superficial structures drain to (lymph)
Axillary nodes
90
Where are the most common fractures of the ribs and why?
Between 3 and 10
| • Ribs 1 and 2 are well protected and the last 2 give way (however they may penetrate)
