Intro To The Thorax Flashcards
1
Q
What is the thorax?
A
- found between neck and abdomen
- consists of thoracic cavity, its contents and the wall that surrounds it
2
Q
What is contained with the thoracic cavity?
A
- heart
- lungs
- oesophagus
- part of trachea
- major blood vessels
3
Q
What bones make up the thoracic wall?
A
- sternum
- thoracic vertebrae
- ribs
4
Q
Other than bones, what makes up the thoracic wall?
A
- costal cartilage of ribs
- intercostal muscles
- arteries, veins and nerves that supply it
5
Q
What are the three segments of the sternum?
A
- manubrium
- body
- xiphoid process
6
Q
What are true ribs?
A
- ribs that are attached directly to the sternum via their costal cartilage
- ribs 1-7
7
Q
What are false ribs?
A
- ribs with indirect attachment to the sternum
- their costal cartilage connects to the cartilage of of the rib above
- ribs 8-10
8
Q
What are free/floating ribs?
A
- these do not attach to the sternum at all, even indirectly
- they end in posterior abdominal musculature
- usually 11th and 12th ribs, sometimes the 10th
9
Q
Which ribs are typical and what are their components?
A
- ribs 3-9
- head
- crest of head
- neck
- tubercle
- body
- costal angle
- costal groove
10
Q
Which ribs are atypical?
A
- 1, 2 and 10-12
11
Q
Why is the first rib atypical?
A
- single facet on its head for articulation with T1 only
- two transversesly directed grooves cross superior surfacae for the subclavian vessels
- these grooves are separated by a scalene tubercle and ridge
- anterior scalene muscle is attached to scalene tubercle
12
Q
Why is the second rib atypical?
A
- rough area on the upper surface called the tuberosity for serratus anterior
- part of serratus anterior attaches here
13
Q
Why are ribs 10-12 atypical?
A
- 10-12 have one facet on their heads and so articulate with only one vertebra
- ribs 11 and 12 are short and have no neck or tubercle
14
Q
Describe the head of typical ribs.
A
- wedge shaped
- 2 facets, one for corresponding vertebra and one for vertebra above it
- facets separated by crest of the head
15
Q
Describe the neck of typical ribs.
A
- connects the head of the rib with the body at the level of the tubercle
16
Q
Describe the tubercle of typical ribs.
A
- located at the junction of the neck and body
- smooth articular part articulates with corresponding transverse process of the vertebra
- rough nonarticular part provides attachment for costotransverse ligament
17
Q
Describe the body of typical ribs.
A
- thin, flat and curved
- curved most markedly at costal angle where ribs turns anterolaterally
- concave internal surface has a costal groove paralleling the inferior border of the rib which provides some protection for intercostal nerves and vessels.
18
Q
Other than where the ribs turn anterolaterally, what else does the costal angle demarcate?
A
The lateral limit of attachment of the deep back muscles to the ribs
19
Q
What is the purpose of costal cartilage?
A
- to prolong the ribs anteriorly
- contribute to elasticity of thoracic wall providing a flexible attachment for their anterior tips
20
Q
What is the costal margin?
A
Formed by ribs 8, 9 and 10’s costal cartilage attaching the cartilage above it.
21
Q
What are the typical features of vertebrae?
A
- body
- vertebral arch
- spinous process
- transverse processes
- articular processes
- pedicles
- lamina
22
Q
What are the characteristic features of thoracic vertebrae?
A
- bilateral costal facets/demifacets on the vertebral bodies for articulation with the head of the ribs
- costal facets on the transverse processes for articulation with the tubercles of the ribs (excluding inferior 2/3 thoracic vertebrae)
- long, inferiorly slaning spinous processes
23
Q
What bony landmark can be used to identify the level of the 2nd rib?
A
The sternal angle
24
Q
List the functions of the thoracic wall.
A
- protects the contents of the thoracic cavity
- provides the mechanics for breathing
- provides for attachment of neck, back, upper limb and abdominal musculature
25
What are the apertures of the thoracic wall?
- superior thoracic aperture
| - inferior thoracic aperture
26
What passes through the superior thoracic aperture?
- structures to and from the neck and upper limbs
- trachea
- oesophagus
- nerves and vessels that supply and drain the head, neck and upper limbs
27
What is the relevance of the inferior thoracic aperture?
Provides a rim to which the diaphragm is attached. Structures which need to pass between the thorac and the abdomen traverse openings in the diaphragm.
28
List some diaphragmatic apertures and the structures which pass through them.
- the caval opening for the inferior vena cava and terminal branches of right phrenic nerve
- the oesophageal hiatus for the oesophagus, right and left vagus nerves and oesophageal branches of gastric artery/vein
- the aortic hiatus for the aorta, thoracic duct and azygous vein
29
At which vertebral level would the caval opening be found?
T8
30
At which vertebral level would the oesophageal hiatus be found?
T10
31
At which vertebral level would the aortic hiatus be found?
T12
32
List the joints found in thoracic wall.
- intervertebral
- costovertebral (joints of head of ribs and costotransverse)
- costochondral
- interchondral
- sternocostal
- sternoclavicular
- manubriosternal
- xiphisternal
33
Describe the intervertebral joints of T1 - T12.
Type: symphysis (secondary cartilaginous)
Articulation: adjacent vertebral bodies bound together by IV disc
Ligaments: anterior and posterior longitudinal
Comments: movement mostly limited to small degress of rotation
34
Describe the costovertebral joints, both for joints of head of ribs and costotransverse.
Type: synovial plane joints
Articulation: head of each rib with superior demifacet of corresponding vertebra and inferior demi facet of superior vertebra and joinging IV disc; tubercle of the rib with transverse process of corresponding vertebra
Ligaments: radiate and intra-articular ligaments of head of rib; lateral and superior costotransverse
Comments: heads of ribs 1, 11 and 12 articulate only with vertebal body of same number; ribs 11 and 12 do not articulate with transverse process of vertebra of same number.
35
Describe the costochondral joints.
Type: primary/hyaline cartilaginous
Articulation: lateral end of costal cartilage with sternal end of rib
Ligaments: cartilage and bone bound together by periosteum
Comments: no movement normally occurs at this joint
36
Describe the interchondral joints.
Type: synovial plane joint
Articulation: between costal cartilages of 6 and 7, 7 and 8, 8 and 9 (ribs)
Ligaments: interchondral ligaments
Comments: articulation between costal cartilages of ribs 9 and 10 is fibrous
37
Describe the sternocostal joints.
Type: 1st = primary cartilaginous joint; 2nd - 7th = synovial plane joints
Articulations: 1st costal cartilage with manubrium of sternum; 2nd - 7th costal cartilages with body of sternum.
Ligaments: anterior and posterior radiate sternocostal, intra-articular
Comments: articular cavities are often absent, fibrocartilage covers articular surfaces
38
Describe the sternoclavicular joints.
Type: saddle type of synovial joint
Articulation: sternal end of clavicle with manubrium of sternum and first costal cartilage
Ligaments: anterior and posterior sternoclavicular, costoclavicular
Comments: this joint is divided into 2 compartments by an articular disc
39
Describe the manubriosternal joint.
Type: secondary cartilaginous
Articulation: between manubrium and body of sternum
Comments: this joint will often fuse and become synostoses in older people
40
Describe the xiphisternal joint.
Type: primary cartilaginous
Articulation: between xiphoid process and body of sternum
Comments: this joint often fuses and becomes synostoses in older people
41
Describe the diaphragm.
Attachments: L1 - L3 vertebrae, inferior 6 costal cartilages and adjacent ribs, xiphoid process
Innervation: phrenic nerve (C3-C5_
42
List the muscles of the thoracic wall.
- serratus posterior superior
- serratus posterior inferior
- levator costarum
- intercostal muscles
- transverse thoracis
43
Describe serratus posterior superior.
Superior attachment: nuchal ligament, spinous processes of C7-T3
Interior attachment: superior borders of ribs 2-4
Innervation: 2nd - 5th intercostal nerves
Main action: proprioception, elevate ribs
44
Describe serratus posterior inferior.
Superior attachment: spinous processes of T11-L2
Interior attachment: inferior borders of ribs 8 - 12 near their angles
Innervation: anterior rami to T9-T12 spinal nerves
Main action: proprioception, depress ribs
45
Describe levator costarum.
Superior attachment: transverse processes of C7-T11
Interior attachment: subjacent ribs between tubercle and anlge
Innervation: posterior primary rami of C8 - T11 nerves
Main action: elevate ribs
46
Describe the intercostal muscles.
Superior attachment: inferior border of the ribs
Interior attachement: superior border of rib below
Innervation: intercostal nerve
47
What is the main action of the external intercostal muscles?
- to elevate the ribs during forced inspiration
48
What is the main action of the internal and innermost intercostal muscles?
- interosseous part depresses the ribs during forced respiration
- interchondral part evelates ribs during forced respiration
49
In which direction do the muscle fibres of the external intercostal muscles run?
Anteroinferiorly
50
In which direction do the muscles fibres of the internal intercostal muscles run?
Posteroinferiorly
51
Describe the subcostal muscle.
Superior attachment: internal surface of lower ribs near their angles
Interior attachment: superior borders of 2nd or 3rd ribs below
Innervation: intercostal nerve
Main action: probably act similarly to internal intercostal muscles
52
Describe transversus thoracis.
Superior attachment: posterior surface of lower sternum
Interior attachment: internal surface of costal cartilages 2-6
Innervation: intercostal nerve
Main action: weakly depress ribs, possibly proprioception
53
What is the significance of the ribs sloping inferiorly in relation to elevation of the ribs?
Increases the anterioposterior and lateral dimensions of the thorax
54
What is contained in the intercostal neurovascular bundle?
(Superior to inferior)
- intercostal vein
- intercostal artery
- intercostal nerve
- a collateral branch also exists inferiorly
55
Which anterior rami form the intercostal nerves?
T1 - T11
56
Which anterior rami forms the subcostal nerve?
T12
57
Briefly describe the intercostal arteries.
- posterior and anterior anastomose (good back up system)
- posterior intercostal arteries originate from aorta
- anterior intercostal arteries originate from internal thoracic artery or its branches
58
Describe the internal thoracic artery.
- originates from the subclavian artery
- bifurcates into musculophrenic and superior epigastric arteries
- if there is a stricture of the proximal aorta the internal thoracic arteries and anterior intercostal arteries can expand to maintain a blood supply
59
List the three compartments of the thoracic cavity.
- left and right pleural cavites
| - mediastinum
60
List the layers of the pericardium.
(From innermost to outermost)
- visceral layer serous pericardium
- parietal layer serous pericardium
- fibrous pericardium
61
What are the 2 pleural layers of the pleural cavities?
(Innermost to outermost)
- visceral pleura
- parietal pleura
62
Where is the pericardial cavity found?
Between the visceral and parietal layers of serous pericardium.
63
Where are the pleural cavities found?
Between the visceral and parietal pleura.
64
What is the importance of the thin layer of fluid in the pericardial and pleural cavities?
It provides lubrication. This is important as the heart and lungs are constantly expanding and contracting.
65
What is a serous membrane composed of?
Mesothelium = a layer of simple squamous epithelial cells supported by connective tissue.
66
The parietal pleura can be subdivided according to the part of the body that it comes in contact with. List the subdivisions.
- mediastinal
- cervical
- costal
- diaphragmatic
67
Where are the visceral and parietal pleura continuous with each other?
At the hilum of the lungs.
68
What are the pleural recesses?
Potential spaces that the lungs can move into during inspiration.
69
What is the clinical important of the pleural recesses?
They provide a location where fluid can accumulate.
70
What are the two pleural recesses present in each pleural cavity?
- costodiaphragmatic
| - costomediastinal
71
What is thoracentesis?
A procedure to remove fluid or air from around the lungs. A needle is inserted through the chest wall into the pleural space.
72
Describe a thoracentesis procedure.
- the patient sits upright
- hypodermic needle inserted into 9th intercostal space in the midaxillary line during expiration
- needle should be angled upward
- needle inserted superior to rib, high enough to avoid damage to collateral vessels
- the needle passed through the intercostal muscles and costal parietal pleura into the pleura cavity
- fluid/air/blood/pus removed
73
What are the surface landmarks of the thorax?
- jugular/suprasternal notch
- sternal angle
- anterior median line
- midclavicular lines
- axillary fossa
- anterior axillary line
- midaxillary line
- posterior axillary line
74
Describe the sternocleidomastoid muscle.
Origin: sternal head - anterior surface of manubrium sterni; clavicular head - upper surface of medial third of the clavicle.
Insertion: lateral surface of mastoid process of temporal bone and adjacent part of superior nuchal line.
Innervation: Spinal accessory nerve (CN XI), proprioception from cervical plexus.
Main action: one muscle - head tipped to shoulder on same side and rotated to look at opposite side, two muscles - head moves forwards. May be involved in forced expiration.
75
Where does the lateral thoracic artery originate from and what does it supply?
Origin: first part of axillary artery and runs across first intercostal space to uppe thoracic wall.
Supplies: upper thoracic wall.
76
Where does the internal thoracic artery originate from and what does it supply?
Origin: the inferior surface of the first part of the subclavian artery opposite the thyrocervical trunk.
Supplies: intercostal spaces, breast, transversus thoracis, anterior mediastinum.
77
What structures drain into the internal thoracic veins and where does it then drain to?
It drains to the braciocephalic veins after receiving deoxygenated blood from the 8-10th intercostal muscles, transversus thoracis and sternal region.
78
Where does the long thoracic nerve originate from and what does it innervate?
Origin: ventral rami of C5, C6 and C7
Innervates: serratus anterior
79
Describe pectoralis major.
ORIGIN: clavicular head - anterior surface of medial half of calvicle; sternocostal head - anterior surface of sternum, superior six costal cartilages and aponeurosis of external oblique muscles.
INSERTION: lateral lip of intertubercular sulcus of humerus.
INNERVATION: lateral and medial pectoral nerves.
MOVEMENTS: adducts and medially rotates humerus, draws scapula anteriorly and inferiorly. Acting alone, clavicular head flexes humerus and sternocostal head extends it from flexed position.
80
Describe pectoralis minor.
ORIGIN: 3rd - 5th ribs near their costal cartilages.
INSERTION: medial border and superior surface of coracoid process of scapula.
INNERVATION: medial pectoral nerve
ACTION: depresses shoulder, pulls scapula forward, raises ribs in inspiration when scapula is fixed.
81
Describe serratus anterior.
ORIGIN: exteral surface of lateral parts of ribs 1 - 8
INSERTION: anterior surface of medial border of scapula.
INNERVATION: long thoracic nerve
ACTION: protracts scapula and holds it against thoracic wall, rotates scapula.
82
List the scalene muscles.
- scalenus anterior
- scalenus medius
- scalenus posterior
83
Which muscles do the brachial plexus and axillary artery pass between?
Scalenus anterior and scalenus medius.
84
Which muscles does the subclavian vein pass between?
Scalenus anterior and sternocleidomastoid.
85
What surgical procedure uses the internal thoracic artery?
Coronary artery bypass grafts
86
At what vertebral level is the sternal angle?
At level of T4 and T5 IVD posteriorly
87
What structures are transected by a horizontal section through the sternal angle?
* RATPLANT*
- 2nd Rib
- Aortic arch
- bifurcation of Trachea
- Bifurcation of pulmonary trunk
- left recurrent laryngeal/ligamentum arteriosum
- Azygous vein
- nerves - cardiac plexus
- thoracic duct
