The thorax, tracheobronchial tree and lungs Flashcards
What are the borders of the superior thoracic aperture?
T1 vertebra
Left and right 1st rib
Sternum (manubrium)
Which bony anomaly could cause injury to the vessels passing in and out of the superior thoracic aperture? What symptoms might they get?
An extra cervical rib
Patient may present with a cold limb, weak pulse, or tingling in the upper limb
Compression of which nerves can cause atrophy of the 1st dorsal webspace?
C6 and C7
What are the borders of the inferior thoracic aperture?
Costal margin – lower border of costal cartilage
Ribs 10-12
Diaphragm crura attach to lumbar vertebrae
Which nerve provides motor and sensory innervation to the diaphragm?
Phrenic nerve (C3,4,5)
Intercostal nerves provide what to the diaphragm?
Additional sensory innervation on the periphery
Which specific element of cardiac surgery could cause injury to the phrenic nerve?
Saline slush from myocardial preservation
Which pathology would unilateral phrenic nerve injury cause?
Hemidiaphragmatic palsy
At which vertebral level does the IVC pass through the diaphragm?
T11
At which vertebral level does the oesophagus pass through the diaphragm?
T11-12
At which vertebral level does the aorta pass through the diaphragm?
T12
What are the two types of diaphragmatic hernia, where do they occur, and what do they involve?
Bochdalek hernia – occurs posterolaterally and involves abdominal organs such as liver pushing through the diaphragm into the chest cavity
Morgagni hernia – occurs retrosternally
What kind of condition / movement might a patient present with when breathing with broken ribs? How does this movement differ from usual conditions?
Flail chest – paradoxical breathing where the detached portion of rib cage moves inward during inhalation and outward during exhalation
What is the vertebral level of the jugular (suprasternal) notch?
T2 or T3
The sternal angle sits at which IV disc?
T4-T5 IV disc
What is the vertebral level of the xiphoid process?
T9
Which costal cartilage is lateral to the manubriosternal joint?
2nd costal cartilage
The mediastinum can be divided into superior and inferior parts by what?
Sternal plane – T4-T5 IV disc
What are the 3 rib classifications + which ribs do they include?
Vertebrosternal – ribs 1-7
Vertebrocostal – ribs 8-10
Floating – ribs 11 + 12
Between which muscles is the thoracic neurovascular bundle?
Internal and innermost intercostal muscles
Which area of the intercostal space should chest drains be inserted and why?
Inferior part of the intercostal space to avoid damaging the main neurovascular bundle
What is the origin of the intercostal nerves?
Ventral rami of spinal nerves
What are the 2 main branches of the intercostal nerves?
Lateral cutaneous branches and anterior cutaneous branches
Describe the blood supply to the thorax.
Posterior intercostal arteries arise from the descending aorta and anastomose with the anterior intercostal arteries which arise from the internal thoracic artery and the musculophrenic artery
In aortic coarctation, what is the route that blood flows to reach the descending aorta?
Internal thoracic artery – anterior intercostal artery – posterior intercostal artery – descending aorta
Chronic use of collateral flow through the intercostal arteries can cause which radiological finding? Why does this occur?
Rib notching – where the extra pressure in the intercostal arteries causes the inferior rib edges to remodel
Describe the venous drainage of the thorax.
Right sided structures drain into the azygous vein, which drains into the SVC
Left sided structures drain into either the accessory azygous vein or the hemiazygous vein, which cross the midline to drain into the azygous vein, and into the SVC
The very upper spaces drain straight into the right and left brachiocephalic veins, which unit to form the SVC
The respiratory diverticulum, which is an outgrowth of the gut tube, appears at what stage in gestation?
4 weeks
What are the stages of growth starting from the respiratory diverticulum?
Respiratory diverticulum – lung/bronchial buds – buds grow into splanchnopleuric mesoderm
Name 2 embryological defects that can occur during the separation of the oesophagus from the trachea.
Proximal oesophageal atresia with a distal fistula
Fistula
At which week gestation does respiratory epithelia begin developing in the lungs?
Week 26
What are the fissures of each lung?
Right – oblique + horizontal
Left – oblique
What is atelectasis?
The partial or complete collapse of the lung or section of the lung
What kind of blood do the pulmonary arteries carry and from where?
Pulmonary arteries carry deoxygenated blood from the right ventricle of the heart to the lungs
What kind of blood do the pulmonary veins carry and from where?
Pulmonary veins carry oxygenated blood from the lungs to the heart
The pulmonary veins enter which section of the heart?
Left atrium
Which nerves pass anterior and posterior to the hilum of the lungs?
Phrenic nerves pass anterior to the hilum
Vagus nerves pass posterior to the hilum
Which nerves that innervate the larynx branch off the vagus nerve?
Recurrent laryngeal nerves
What is the position that the right recurrent laryngeal nerve recurs?
Right lung apex under the right subclavian artery
What is the position that the left recurrent laryngeal nerve recurs?
Aortic arch
Which vascular pathology could cause paralysis of the left side of the larynx and how?
An aortic arch aneurysm, by compressing or damaging the left recurrent laryngeal nerve
Where is a needle decompression to correct a pneumothorax carried out?
2nd intercostal space at the midclavicular line
At which vertebral level does the trachea bifurcate?
T6
Which muscle completes the posterior aspect of the trachea?
Trachealis
If food is aspirated, which bronchus is it more likely to pass into and why?
Right – because it is wider and more vertical than the left bronchus
What are bronchopulmonary segments?
The smallest functionally independent regions of the lungs that can be resected without affecting other regions
How many bronchopulmonary segments does the right lung have?
10
How many bronchopulmonary segments does the left lung have?
8-9
How do pulmonary arteries travel within the bronchopulmonary segments?
With bronchi & bronchioles
How do pulmonary veins travels within the bronchopulmonary segments?
Between segments
When a patient is supine, which segment of the lungs will struggle to drain the most since it is most inferior?
The superior segment of the lower lobe
What is the key difference between the composition of the walls of bronchi and bronchioles?
Bronchi contain cartilage, bronchioles do not
How do parasympathetics affect the bronchioles?
Constricts bronchioles
How do sympathetics affect the bronchioles?
Dilates bronchioles
Which arteries supply oxygenated blood to the lung tissues (not for ventilation)?
Bronchial arteries
What is the lymph drainage route from the lungs?
Hilar nodes
Subcarinal nodes
Paratracheal nodes
All to right lymphatic duct, which dumps into the right subclavian vein, except for the left superior lobe, which drains into the thoracic duct and dumps into the left subclavian vein
