Gross Anatomy of Lungs Flashcards
(113 cards)
1
Q
Thorax definition
A
superior component of the trunk, connecting the neck with the abdomen
an irregular cylinder with an opening at each end
2
Q
what are the openings of the thorax called + what communicates?
A
superior thoracic aperture- thoracic inlet formed by the first thoracic vertebra, the first pair of ribs and the superior surface of the manubrium of the sternum- neck and upper limb
inferior thoracic aperture- thoracic outlet- twelfth thoracic vertebra, eleventh and twelfth pair of ribs and the inferior costal cartilages
3
Q
what separates the thorax and the abdomen?
A
muscular sheet of diaphragm
4
Q
thoracic wall definition
A
the boundary of the thoracic cavity
5
Q
what forms the thoracic wall?
A
bony skeletal part- rib cage- thoracic cage comprised of the sternum, thoracic vertebrae, ribs and costal cartilages
the rest- intercostal muscle, skin and fasciae
6
Q
function or thoracic wall
A
protection of thoracic viscera
dynamic generator of change in intrathoracic pressure to drive ventilation
7
Q
What two things must the thoracic wall be + how is this achieved?
A
rigid- bony components
mobile- various parts of articulation between the bones
8
Q
How does the upper limb articulate with the thorax?
A
clavicle and scapula, which form the pectoral girdle, are closely associated with the thoracic wall
9
Q
Three parts of the sternum + any important regions
A
manubrium, body of sternum and cartilaginous xiphoid process- level T9/10
suprasternal notch- jugular notch- level of T2
sternal angle- manubriosternal joint at level of lower T4 vertebrae- secondary cartilaginous joint- palpable landmark
sternal plane at T4/T5- level of bifurcation at carina
10
Q
Origin of sternum
A
developmentally forms from a series of smaller bones called sternebrae, fusion of which creates the body of the sternum
more superior sternebrae form the manubrium
11
Q
costal cartilage definition
A
bars of hyaline cartilage that serve to prolong the rib forward and contribute to the elasticity of the walls of the thorax
12
Q
where is costal cartilage found?
A
only found at the anterior ends of the ribs, providing medial extension
13
Q
Where do the first two pairs of costal cartilages articulate?
A
manubrium of the sternum
joint between the manubrium and the body of sternum
14
Q
how many pairs of ribs?
A
12
15
Q
What may also be the case with the number of ribs + significance?
A
extra or absent ribs in some individuals
clinically significant if there is a pair of cervical ribs at the superior thoracic aperture, which may compress neurovascular structures transversing the narrow space
16
Q
joint name between sternum and costal cartilage
A
sternocostal joints
17
Q
what are the posterior joints called?
A
costovertebral joints with the ribs articulating with the twelve thoracic vertebrae
18
Q
Which rib articulates with which vertebrae?
A
head of rib articulates with the vertebral body at the same level and that of the vertebra above
first, eleventh and twelfth ribs articulate only with respective thoracic vertebra T1, T11 and T12
19
Q
rib structure
A
anterior portion contain a piece of costal cartilage
curved body
angle
neck
tubercle- a small bump on the neck articulates with the vertebral transverse process at the same level
head with two articular facets
first rib is particularly flattened
20
Q
What are the different ribs referred to as?
A
true ribs- upper seven, articulate directly via their costal cartilages with the sternum
false ribs- rib pair 8 -10 articulate with the costal cartilage of the ribs above
floating ribs- 11-12 have no anterior articulation
21
Q
Diaphragm definition
A
domed musculotendinous sheet, being fibrous in its central part called the central tandon
22
Q
diaphragm structure
A
both the left and right dome are associated with the lobe above it
muscular part is attached to the xiphoid process and the 11th and 12th rib, lower costal cartilages and the first to third lumbar vertebrae
veretbral attachments are via muscular slopes called crura
right crus originates from L1-L3 and left from L1-L2 vertebral bodies
costophrenic angle- peripheral edge of diaphragm with the thoracic wall
23
Q
What happens to the costophrenic angle upon inspriration?
A
diaphragm flattens angle decreases
24
Q
Where does innervation of the diaphragm originate?
A
sensory and motor innervation from right and left phrenic nerves originating from C3, C4 and C5
C3,4,5 keep the diaphragm alive
25
structures that transverse the diaphragm
inferior vena cava at T8- through opening on the right of central tendon
oesophagus and vagus nerves passes through fibres of the left crus at T10
Aorta and thoracic duct of the lymphatic system- pass between crura at the T1 level
26
Where do the sympathetic chains pass?
along the posterior thoracic wall and pass behind the diaphragm at a level similar to the aorta
27
Where do the phrenic nerves pass?
descend through the thorax on either side of the mediastinum to reach the diaphragm where they penetrate its substance to innervate it.
28
Other innervation of diaphragm
peripheral edge of diaphragm receives some sensory innervation from intercostal nerves
29
What is referred pain?
Pain perceived at a location other than the site of the painful stimulus.
It is a result of a network of interconnecting sensory nerves that supplies many different tissues
30
Where may the diaphragm pain be referred to?
right shoulder region or right hypochondrium, due to the distal origin of these diaphragmatic nerves C3,4,5
31
condition affecting the lung + cause
hemidiaphragmatic palsy
paralysis during neck surgery may damage C3,4,5 which prevents motor innervation, so one half of the diaphragm doesn't move during inspiration
32
how many layers of intercostal muscle + names?
external and internal intercostal muscles- most developed and fill the spaces between the adjacent ribs
innermost intercostal muscles
33
Which are the most well developed muscles?
external and internal intercostal
34
what are the 3 layers continuous with ?
counterparts to the three layers that make up the anterolateral walls of the abdomen
35
what may the innermost intercostal muscles form?
some anatomically recognised muscle groups such as transversus thoracic and subcostales
36
Explain the fibres of the external intercostal muscles
rub forwards and downwards rom the tubercles of the ribs
become membranous close to the sternum
37
explain fibres of the internal intercostal muscles
thickest closest to the sternum
fibres run at right angles to those of the external intercostals and become membranous at the angles of the ribs
38
what achieves changes in thoracic volume?
diaphragm and intercostal muscles, latter driving the movement of the ribs
39
What drives ventilation at rest?
contraction and relaxation of the diaphragm
40
accessory muscles of breathing
sternocleidomastoid, scalenes and quadratus lumborum
41
What happens during inspiration?
1. external intercostal muscles contract, pulling ribs outwards and upwards, which increases the transverse and anteroposterior diameters of the thorax
2. diaphragm contracts, increasing the vertical dimension of the thoracic cage
42
How do the ribs differ + what this causes during inspiration?
different shape and dimension of different ribs results in a slightly different range of movements for each rib
sternal ends of the ribs are lower than their vertebral ends and elevation of the ribs at their costovertebral joints results in a lifting of the sternum upwards and outwards in a 'pump handle' movement
the most lateral part of the rib is inferior to its vertebral attachment, resulting in the rib also being moved outwards as it is elevated in a 'bucket handle' movement
43
Where is the pump handle movement most pronounced? + what it causes
second to sixth ribs
increases anteroposterior diameter of thorax
44
where is the bucket handle movement most pronounced? + what it causes
lower ribs
increases the transverse diameter of the thoracic cage
45
When are accessory muscles utilised?
during deep or forced inspiration
46
explain actions of accessory muscles
1. neck muscles, sternocleidomastoid and the scalenes pull upon the first rib, lifting the sternum- further increasing the anteroposterior and vertical dimension
quadratus lumborum aids the contraction of the diaphragm by pulling upon the twelfth rib
47
explain expiration
predominantly passive process, driven by the relaxation of the diaphragm and external intercostal muscles and recoil of the elastic lung tissue itself
forced expiration depends upon the contraction of the inner intercostal and innermost intercostal muscles, which depress the ribs
48
accessory muscles that aid expiration + function
abdominal muscles- external oblique and rectus abdominis
further depress the thoracic cage while increasing intra abdominal pressure which pushes the diaphragm superiorly
49
what are the intercostal spaces?
eleven anatomical spaces present between the typically 12 pairs of ribs
contain the intercostal muscle, nerves, arteries and veins, along with the associated lymph vessels and nodes
50
organisation of the main neurovascular bundle
superior to inferior
vein - artery - nerve
51
What are the intercostal nerves?
ventral rami of the T2-T11 spinal nerves
ventral ramus of the first thoracic spinal nerve contributes to a large branch called the brachial plexus
a smaller branch passes into the first intercostal space as the first intercostal nerve
52
What is the ventral ramus of the 12th thoracic spinal nerve called?
subcostal nerve- innervates the lower part of the abdominal wall
53
function and structure of the intercostal nerves
innervate the intercostal muscles and provide branches to the parietal pleura and their respective dermatomes
lateral cutaneous branch pierces the intercostal muscle and provides sensation to the skin of the lateral thoracic wall
anterior cutaneous branch provides sensation to the anterior thorax and abdomen skin
54
how can the segmental innervation be viewed clinically?
shingles- reactivation or varicella zoster virus lying dormant in a dorsal root ganglion from an earlier chicken pox infection forms a rash following the dermatomes
55
Where is a chest drain inserted? + why?
lower part of of the intercostal space, to avoid damage to main neurovascular bundle
56
What are the main arteries in the lungs+ what do they form?
anterior and posterior intercostal arteries which form an anastomosis
57
Where are the intercostal arteries derived from?
anterior- segmental vessels from the internal thoracic branches of the subclavian arteries- which run deep to the thoracic wall 1cm lateral to the sternum
posterior- segmental branches of the descending thoracic aorta
most superior two posterior are usually branches of a superior intercostal artery, derived from the costocervical trunk o the subclavian arteries
58
What are the internal thoracic arteries usually used for?
coronary artery bypass graft- CABG
59
aortic coarctation definition
congenital condition whereby the aorta is narrow, usually in the area where the ductus arteriosus inserts
60
What can be used to visualise a coarctation?
cardiac magnetic resonance angiograph
61
main veins in lungs + where they drain
anterior and posterior intercostal veins
superior two veins drain into brachiocephalic veins
most others drain into the azygos venous system present on the posterior thoracic wall
intercostal veins on the right side join onto the azygos vein which drains into the superior vena cava
intercostal veins on the left are drained by accessory hemiazygos vein andlower hemiazygos vein
62
Where do the hemiazygos veins cross to join the azygos vein?
the midline
63
Where are the lymph nodes located?
alongside the internal thoracic arteries within the posterior intercostal spaces, where lymphatic vessels lie alongside the intercostal vessels
64
What are the lymph nodes in that position called?
Parasternal nodes
65
Important note in regards to breast tissue and drainage
lymphatic vessels from the medial portions of each breast drain to parasternal nodes
metastases from a breast tumour may drain to the contralateral thoracic wall and breast
66
Where do the lymph nodes drain?
thoracic duct carries lymph from all body regions except for the right side of the thorax, head, neck and right upper limb
67
What does the thoracic duct form and where?
thoracic duct forms within the abdomen as the cisterna chyli at the level of the first lumbar vertebra and ascends anterior to the thoracic vertebrae, inferior lying to the right side of the aorta
crosses to the left, where it receives lymphatic vessels from the left posterior intercostal spaces
reaches anterior to join and drain the venous angle between the left internal jugular and subclavian veins
the right lymphatic duct drains into the venous angle between the right internal jugular and subclavian veins
68
chylothorax definition
wall of thoracic duct is damaged, lymphatic fluid may leak into pleural cavitites
69
What is Horner's syndrome?
compression of the sympathetic chains as they transverse the posterior thoracic wall, typically close to the superior thoracic aperture, by a tumour in the Apex of a Lung and causes drooping of the eyelid- partial ptosis, pupillary constriction- miosis and lack of sweating- anhydrosis
70
What is a tumour in the apex of the lung called?
Pancoast's tumour
71
what type of epithelium are the pleura?
mesothelium
72
What does the mesothelium produce + function?
small amounts of pleural fluid that allows pleural layers to slide past each other without producing friction
73
two types of pleura
visceral- covers the lungs including fissures, which is continuous with parietal at hilum
parietal pleura - lines the walls of the pleural cavity- cervical, mediastinal, diaphragmatic and costal
74
explain innervation of pleura
phrenic nerves- innervate diaphragmatic mediastinal pleura
intercostal nerves- costal pleura
75
What causes the pleura to be kept close together?
normal surface tension, holds both layers close together to form a very small space called the pleural cavity
76
what may go wrong with the pleural cavity?
air- pneumothorax, fluid (blood- haemothorax)
excessive pleural fluid- pleural effusion/ lymph- chylothorax
all in pleural cavity may compress the lung and compromise respiratory function
77
4 parts of parietal pleura
cervical, costal, mediastinal and diaphragmatic
78
what is the costodiaphragmatic recess?
spaces formed by the parietal pleura between the thoracic wall and diaphragm
lung expands into this during deep inspiration
79
where may the recess extend below?
12TH RIB
80
what can cause a pneumothorax?
trauma or interventional procedures that may damage the parietal pleura which results in an ingress of air into the space
trauma- stab injury, rib fracture
underlying lung disease
spontaneous
81
tension pnemothorax definition
a progressive increase in air within the pleural cavity with each breath- the air being unable to escape upon expiration
leads to a rapid deterioration in respiratory function and is a medical emergency
can cause tachypnoea, tachycardia, hypotension
mediastinal shift, tracheal deviation- shift away from affected side
unilateral hyperinflation, hyperresonance and absent breath sounds on affected side
82
Trachea definition
Prominent midline structure, which is palpable in the neck where it lies anterior to the oesophagus
83
What structure is above the trachea + where does it change?
continuous with the larynx
the inferior border of which lies at the fifth/sixth cervical vertebrae
84
trachea structure + function
formed partly by approximately 15 incomplete hyaline cartilage rings which are deficient posteriorly permitting expansion of the oesophagus as swallowed food passes down its length
incomplete part of the C shaped rings of cartilage also provide a site of attachment for the trachealis muscle
85
trachealis muscle function
contract to narrows the airway during coughing to increase the velocity of airflow to help expel any objects irritating the tracheal lining
86
Where does the trachea birfurcate?
at the sternal plane- C5/C6 at the carina
87
where do the bronchi enter the lungs?
Enter the hilum approximately at the T5/T6 level
88
Structure of right bronchus
wider and more vertically orientated
divides into three secondary bronchi- correlating with the number of lobes in each lung
right primary bronchus is shorter, and divides before it enters the lung
89
structure of left bronchus
narrower and more horizontal
divides into two secondary bronchi
secondary bronchi then divide into tertiary/segmental bronchi which serves the bronchopulmonary segments of each lobe
90
How can the tracheobronchil tree be examined?
by bronchoscopy
91
Where are aspirated objects more likely to become lodged?
right bronchus, as wider and more vertical orientation
92
lung margins
apex, reaches the neck region above the clavicle- suprapleural fossa and is palpable here
apex separated from neurovascular structures passing through the neck by a sheet of connective tissue- suprapleural membrane
lateral surface of lung in contact with the thoracic wall is the costal surface
inferior diaphragmatic surface of each lung is called the base
medially each lung presents a surface in contact with the mediastinum, called the mediastinal surface
mediastinal surface has a root/hilum where the bronchi, blood vessels, nerves and lymphatic vessels enter and leave the lung
93
lung structure
left lung has two lobes
right lung has three lobes
both lungs divided into upper and lower lobes by the oblique fissure which passes through the entire depth
right lung has an additional horizontal fissure, separating the middle lobe from the upper lobe
upper lobe of left lung demonstrates a cardiac notch, inferior extension of which is called the lingula, which is a developmental homologue of the middle lobe of the right lung
94
what can each lobe be divided into?
bronchopulmonary segments, each associated with the terminal bronchi
95
How many segments in each lung?
10 in right
8-10 in left, as some segments duse
96
Explain structures of segments
each segment is separated by sheets of connective tissue
blood supply is segmental, with each segment receiving a branch from the pulmonary artery
97
clinical relevance of bronchopulmonary segments
knowledge of the anatomical arrangement is of importance in facilitating postural drainage of fluid or lung secretions
in supine patients the fluid will drain into the superior apical segments of the lower lobe
98
where do the bronchi lie relative to the arteries?
lie posterior to the pulmonary arteries of the right lung and inferior to the pulmonary arteries of the left lung at their entry point in the hilum
99
describe vasculature of hymen
Two pulmonary arteries- one right and one left
4 pulmonary veins- one superior and inferior leaving the hilum of each lung. Return oxygenated blood to the left atrium. Normally lie anterior and inferior to the pulmonary arteries and main bronchus
100
What is the pulmonary ligament and where does it lie?
fold of pleural membrane reflected at the junction between parietal and visceral pleura
101
Where do the lung tissue receive their blood supply from?
bronchial arteries originating from the aorta
small in comparison to pulmonary vessels and lie posterior to the main bronchi at the hilum
102
What is a pulmonary embolism?
venous thromboses can enter the lung circulation via a pulmonary artery and cause a blockage
103
explain lymphatic drainage of the lungs
lymphatic vessels surround the bronchial tree to form a deep lymphatic plexus
nodes surrounding the periphery of the lungs deep to the visceral pleura form the superficial lymphatic plexus
lymph from the superficial plexus drains into the bronchopulmonary lymph nodes situated at the hilum of the lung
lymph from the deep plexus drains first to pulmonary lymph nodes surrounding the secondary bronchi and then the bronchopulmonary nodes
bronchopulmonary nodes drain to tracheobronchial lymph nodes surrounding the tracheal birfucation at the carina
then drains to paratracheal nodes
lymphatic drainage from right lung is received by the right lymphatic trunk, as is lymphatic drainage from the lower lobe of the left lung
lymph from superior lobe of left lung drains to the thoracic duct at the left venous angle
104
Where is the apex located?
2cm above the medial clavicle
105
what is MAL?
Mid axillary line- found at the 4th costoclavicular cartilage
106
what is MCV?
mid clavicular line-
107
what is flail chest?
when a rib fracture results in a region of the rib cage becoming disconnected from the chest well.
the segment will then move with the lungs upon inspiration and expiration, not the ribcage
108
what is percussion of the chest?
an assessment technique which produces sounds by the examiner tapping on the patient's chest wall
109
different sounds + what they mean
normal- no problem
dull- abnormal lung density, tumour pleural effusion
hyperresonant - too much air present in lung tissue, emphysema or pneumothorax
110
dullness due to?
heart/ liver
111
auscultation definition
listening to the internal sounds of the body, using a stethoscope
112
different areas of auscultation
heart, breathe sounds over trachea, lung fields
113
lung field definition
region of the body containing a lung
