ANAT: Lungs + Thorax Flashcards
1
Q
which embryological structure gives rise to the diaphragm?
A
- septum transversum
2
Q
what is the pleura?
A
- simple epithelial layer (mesothelium - comes from mesoderm)
- double layered sac (technically one layer that doubles on itself)
- pleural cavity contains fluid to decrease friction during breathing
3
Q
why is the diaphragm innervated by the phrenic nerve?
A
- originated in cervical region and migrated down into thorax
- therefore brought down C3-C5 with it
4
Q
describe the dome shape of the diaphragm
A
- R side: anterior and superior
- L side: inferior and posterior
5
Q
what are the 3 apertures in the bottom of the diaphragm and what structures pass through them?
A
- T8 (caval hiatus): inferior vena cava and R phrenic n.
- T10 (oesophageal hiatus): oesophagus and vagus n.
- T12 (aortic hiatus): aorta and thoracic duct
- I ate 10 Eggs At 12pm
6
Q
which muscles help w/ breathing in the various dimensions?
A
- vertical: diaphragm
- AP/transverse: intercostals
7
Q
why is the pleural cavity called a potential space?
A
- there is basically no space apart from a thin layer of fluid
- if lung collapses or there is a haemothorax or pneumothorax, this space can get bigger
8
Q
pulmonary ligament
A
- connects visceral and parietal pleura
9
Q
what is a point of reflection and where are they located in the lungs
A
- when visceral pleura turns into parietal (b/c it wraps around itself)
- costal, diaphragmatic, mediastinal (pulmonary ligament > hilum)
10
Q
what is the costodiaphragmatic recess and what is the other recess?
A
- space between costal and diaphragmatic pleura at the bottom of the lung, where the lung doesn’t completely fill this space
- costomediastinal recess
11
Q
why are the pleura and peritoneum connected in terms of embryology?
A
- parietal/somatic mesoderm lines the posterior body wall (thoracic and abdominal)
- visceral/splanchnic mesoderm covers lungs and GIT
- gut tube grows in the middle
- mesentery (peritoneum) or pulmonary ligament (pleura) is between visceral and parietal
- therefore gives rise to both pleura and peritoneum
12
Q
which layer of the pleura can detect pain and what are the 4 regions? which nerve is each region innervated by?
A
- parietal (contains somatic innervation whereas visceral is autonomic)
- cervical and costal: intercostal nn.
- diaphragmatic: phrenic (centrally) and intercostal (peripherally)
- mediastinal: phrenic n.
13
Q
what is surface projection of lungs
A
- anatomical locations of where the visceral pleura is located (i.e. outline of the lungs)
14
Q
root vs hilum of lung
A
- root: bundle of structures that pass through the lung e.g. bronchi, arteries, veins, nerves, lymphatics
- hilum: the gateway through which these structures pass
15
Q
desceribe the course of the recurrent laryngeal nerves and when are they at risk of damage?
A
- starts at larynx, comes down and loops around arch of aorta (L side) or subclavian a. (R side)
- at risk of damage in patent ductus arteriosus repair since L side loops around arch of aorta
16
Q
lung fissures
A
- fissures separate each lobe
- R lung has a horizontal fissure superiorly and oblique fissure inferiorly
- L lung has one oblique fissure
- both oblique fissures are hands in pockets direction
17
Q
where can pleuritic pain be referred to?
A
- parietal pleura innervated by phrenic and intercostal nn.
- phrenic n. = upper limbs, shoulder and neck
- intercostal nn. = chest wall
18
Q
describe the structure and contents of the mediastinum
A
SUPERIOR MEDIASTINUM: above the heart/rib 2
- aortic arch, SVC, trachea, oesophagus, thymus
INFERIOR MEDIASTINUM
- anterior: phrenic n.
- middle: heart, ascending aorta, SVC, PT, pulmonary veins, bronchi
- posterior: oesophagus, descending aorta, vagus n.
19
Q
what is the mediastinum
A
- space b/n the lungs
20
Q
boundaries of the mediastinum
A
- anterior: sternum
- posterior: vertebral column
- superior: thoracic inlet
- inferior: diaphragm
- lateral: lungs
21
Q
how to determine where to do a thoracentesis (pleural tap) to relieve pleural effusion?
A
- look for a dull percussion note > indicates fluid
22
Q
how do the bronchi differ and what is the clinical relevance of this? how does the positioning of the person impact this?
A
- R = wider, shorter, more vertical = more aligned with trachea = easier for foreign objects to enter the R lung
- if upright: will enter inferior lobe due to gravity
- if lying on L side: will enter superior lobe
- if lying on R side: will enter middle lobe
23
Q
cardiac notch
A
- indentation on anterior surface of L lung, between the two lobes (inferior to hilum)
- made by L ventricle/apex of heart
24
Q
situs inversus
A
- organs are mirrored
25
where on the lung do the aortic arch and descending aorta make impressions?
- aortic arch: anterior surface of left lung, superior lobe directly superior to hilum
- descending aorta: posterior surface of left lung, inferior lobe
26
normal inferior margin of lung on passive expiration
- 6th costal cartilage (near sternum)
27
impressions on the right lung
- superior lobe: azygous vein, SVC, brachiocephalic vein, 1st rib
- middle lobe: none
- inferior lobe: cardiac notch (RA), oesophagus, IVC
28
draw the two lung hila and label the following:
- bronchi
- pulmonary aa.
- pulmonary vv.
- hilar lymph nodes
memory aid: RALS (right pulmonary artery anterior to right main bronchus, left pulmonary artery superior to left main bronchus)
29
describe the vascular supply of bronchioles
- pulmonary arteries (deox blood) follow the bronchi through the hilum
- BRONCHIAL arteries (ox blood) are smaller and located in the wall of the bronchus
30
draw the azygous venous system
- memory aid: going clockwise, loses a word each time
- i.e. accessory hemiazygous, hemiazygous, azygous
31
difference between phrenic and vagus nerve re: course
- phrenic = anterior to lung hilum, courses along pericardium
- vagus = posterior to lung hilum
- L recurrent laryngeal nerve loops around arch of aorta
- R recurrent laryngeal nerve loops around R subclavian artery
32
how does the innervation of the pleura relate to pain?
- visceral = dull, poorly localised (autonomic)
- parietal = sharp, well-localised pain (somatic)
33
bronchial tree structure
- trachea
- bronchi (div 1-3)
- bronchioles (div 4)
- terminal bronchioles - NO alveoli (div 5-15)
- respiratory bronchioles - alveoli (div 16-18)
- alveolar ducts (div 19-22)
- alveoli (div 23)
34
what is the angle of carina and when can it widen?
- angle between the bifurcation of the trachea at T4/T5 level
- can widen due to mediastinal tumours, lymph node enlargement, collapsed lung etc
35
what structures do the right lymphatic duct and thoracic duct drain?
- thoracic duct: L arm, both legs, abdomen, pelvis, L side of thorax, head and neck > L brachiocephalic v.
- R lymphatic duct: R arm, R side of thorax, head and neck
36
describe the branching of the SVC
- azygous vein drains into it
- SVC branches into L and R brachiocephalic
- brachiocephalic bifurcates into internal jugular medially and subclavian laterally
37
tension pneumothorax Tx
- usually: chest tube 5th intercostal space ('triangle of safety') mid axillary line (longer term air drainage for 1-2 days)
- sometimes: needle decompression 2nd ICS midclavicular (immediate decompression) - usually only do in emergency b/c more accessible if on the R side to avoid heart
38
treatment for pleural effusion
- 'pleural tap' = drain pleural fluid
- needle in 10th/11th ICS from the BACK (costodiaphragmatic recess)
- Pt should therefore be sitting up
39
type I vs type II pneumocyte
- type I: thin and flat, facilitate gaseous exchange
- type II: cuboidal, have microvilli, secrete surfactant
40
other accessory muscles of breathing
- SCM
- scalenes
41
difference in Sx between simple and tension pneumothorax
- simple: normal BP and HR, mild dyspnoea, no tracheal deviation or JVD
- tension: tachycardia, hypotension, severe respiratory distress, contralateral tracheal deviation and JVD
- both have decreased/absent breath sounds on ipsilateral side and hyperresonant percussion
42
PE symptoms
- tachycardia
- pleuritic pain (sharp pain on inspiration)
- low oxygen sats
- haemoptysis
43
types of aortic dissection
- type A: involving ascending aorta (and/or descending) - can cause cardiac tamponade as it is intrapericardial
- type B: NO ascending aorta
