Thorax 7 - Superior & Anterior Mediastinum Flashcards
Where are the vagus and phrenic nerves positioned in relation to each other?
Phrenic nerves lie lateral to the vagus nerves
Which section of the aorta lies in the superior mediastinum?
Aortic arch
In relation to where the common carotid artery arises from the aorta, where does the subclavian arise?
Posterior
Which directions does the aortic arch travel?
Superiorly
Posteriorly
To the left
What landmark marks the superior point of the thymus?
Jugular notch
What landmark marks the inferior point of the thymus?
4th cc
In which mediastinum is the thymus found?
Anterior
Which structures does the thymus lie between?
Posterior to manubrium & body of sternum
Anterior to pericardium
What is the function of the thymus?
To programme T-lymphocytes
Where do the internal jugular and subclavian veins join and become the brachiocephalic vein?
Posterior to the sternoclavicular joint
Which aspect of the arch of the aorta does the LBCV pass closest to?
Anterior
Does the LBCV pass anterior to the manubrium?
No
Where do the RBCV & LBCV meet to become the SVC
Posterior to 1st right cc
Where does the azygos vein join the SVC?
Posterior to 2nd right cc
At what level does the SVC enter the right atrium?
Posterior to 3rd right cc
Is the pulmonary trunk in the superior mediastinum?
No
Is the ligamentum arteriosum in the superior mediastinum?
Yes
What are the boundaries of the anterior mediastinum?
Sternum, pericardium, lungs & pleura
What are the boundaries of the superior mediastinum?
Thoracic inlet, sternal angle (T4/5), posterior to manubrium, anterior to T1-4, oblique from manubrium up to T1, lungs & pleura
Where does the aortic arch lie?
At the level of T4/5
At the level of T3, where do the vagus nerves lie in relation to the phrenic nerves?
Medially & Posteriorly
At what spinal level does the bifurcation of the trachea into bronchi occur?
T5/6
Between what two landmarks does the thymus lie?
Jugular notch
4th CC
From which two arteries does the thymus get its blood supply?
Internal thoracic
Inferior thyroid
Which vein carries blood away from the thymus?
Left brachiocephalic
Where are the right and left BCV’s formed and which veins form them?
Posterior to the sternoclavicular joints.
Internal jugulars and subclavians
Venous drainage:
- Azygos
- Subclavian
- Internal jugular
- LBCV
- posterior chest wall
- UL
- head & neck
- anterior chest wall (via internal thoracic veins)
Which vein do the azygos, subclavian, internal jugular and LBC veins drain to?
SVC
Which veins may be at risk during tracheostomy in children?
Thyroid veins, since in children they may protrude above the manubrium
A key note to remember…
The nerves lie BETWEEN the arteries and veins
Which arteries are contained in the superior mediastinum?
Arch of aorta (NOT descending aorta) BCT Right subclavian Right common carotid Left subclavian Left common carotid
With regard to landmarks, where does the arch of aorta lie?
Sternal angle - T4/5 plane
At which spinal level does the PT bifurcate?
T5
Where does the PT lie in relation to the aorta?
To the left
In which mediastinum does the ligamentum arteriosum lie?
Superior
What are the C shaped rings in the trachea made of?
Hyaline cartilage
What is the carina?
Tracheal bifurcation
Between which spinal levels does the trachea run?
C6 - T4/5
What structure lies between the trachea (anterior) and the oesophagus (posterior)?
Left recurrent laryngeal nerve
When does trachealis muscle contract and when does it relax?
Contracts at rest
Relaxes upon exertion (greater capacity)
At which spinal level does the oesophagus start?
C6
Between which two structures does the thoracic duct lie?
Azygous vein
Thoracic aorta
In which mediastinum does the thoracic duct lie?
Extends from posterior mediastinum up to the superior mediastinum
What assists lymph movement?
Aortic pulsations
At which vertebral level does the thoracic duct cross behind the oesophagus to ascend on its left side?
T4/5
Where does the thoracic duct enter the venous system?
At the junction between the left internal jugular and the left subclavian veins, i.e. the LBCV
What pathology can affect the left recurrent laryngeal nerve and what would the result of this be?
Left lung tumours
Causes hoarse voice
To which lymph nodes does the lung and lung hilum lymph drain to?
Mediastinal
Where can mediastinal lymph nodes be found?
Clustered around the trachea and oesophagus in the superior mediastinum
Where do superior tracheobronchial lymph nodes lie?
Above the carina (tracheal bifurcation)
Where do inferior tracheobronchial lymph nodes lie?
Below the carina
Where might palpable lymph nodes be found in lung tumour cases and why?
Neck - due to communication with deep cervical lymph nodes
Around which structure can anterior lymph nodes be found?
Brachiocephalic veins
