Superior, Anterior and Posterior Mediastina Flashcards
insert superior mediastinum diagram
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Boundaries of the superior mediastinum (5):
- Superiorly: is the superior thoracic
aperture (manubrium, Rib 1, T1) - Inferiorly: marked by the transverse
thoracic plane (sternal angle T4/T5) - Anteriorly: manubrium
- Posteriorly: T1-T4/T5 vertebral bodies
- Laterally: mediastinal pleura
Contents of the Superior Mediastinum (7):
Great Vessels:
- arteries: arch of aorta and branches
- veins: brachiocephalic, superior vena cava
Nerves:
- phrenic nerve
- vagus nerve
Visceral Structures:
- thymus gland (part)
- trachea
- oesophagus
- thoracic duct
Contents of Superior Mediastinum diagram?
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Surface projection of the trachea, oesaphagus and the thoracic aorta
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Each brachiocephalic vein is formed by the union of
an internal jugular vein and a subclavian vein
Veins in the superior mediastinum
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The superior vena cava is formed by
the union of the left and right brachiocephalic veins
Right and Left internal jugular veins on Xray
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Arteries in the superior mediastinum diagram
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What does the brachiocephalic trunk branch into
the right common carotid and the right subclavian arteries
Chest X-Ray
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First Rib Fracture
- combination of injuries, first rib runs under clavicle, hard to access subclavian and stop the bleeding
- high velocity injury: 30% mortality
- Vascular injury: subclavian artery
- Nerve injury: brachial plexus injury
Ligamentum Arteriosumn (4):
- embryological remnant of the ductus arteriosus: which connects the pulmonary trunk and the arch of the aorta
- important in fetal circulation allowing blood to bypass the immature lungs
- closes at birth and remains in the adult as a ligamentous structure ;
- patent ductus arteriosus
Phrenic Nerves:
- originates
- enters mediastinum (which part of mediastinum)
- right hand side runs over
- left hand side over
- motor supply to
- sensory supply to
- pain referral
- originate from the anterior rami of C3,C4,C5
- enters the superior mediastinum between brachiocephalic veins and subclavian arteries passing anterior to main bronchi (hence slightly different on both sides)
- right hand side over pericardium
- left hand side over the ventricles
- motor supply of diaphragm
- sensory supply:
- diaphragm (central region)
- pleura (diaphragmatic and mediastinal)
- can refer pain:
- irritation below diaphragm can be referred to shoulder tip
Vagus Nerves:
- originates
- enters mediastinum (which part)
- fives rise to
- passes into
- right hand side close to
- left hand side close to
- cranial nerve X originate from the medulla
- enter the superior mediastinum medial to the
phrenic nerve and posterior to the sterno-
clavicular joint - gives rise to a recurrent laryngeal branch to
supply the larynx - passes into the posterior mediastinum posterior
to the main bronchi - right hand side vagus nerve close to trachea
- left hand side vagus nerve away from trachea due
to great vessels
Visceral Structures: Trachea:
- which part of the mediastinum
- -
- superior mediastinum
- Tube C-shaped cartilage rings
- trachealis muscle runs posteriorly
- runs from larynx to the bronchi
Which part of the mediastinum is the superior vena cava located?
Superior mediastina
Which part of the mediastinum are the brachiocephalic veins found?
Superior mediastina
Which part of the mediastinum is the left common carotid artery located in? Branch of?
- superior mediastina
- arch of aorta
Which part of the mediastinum is the left subclavian artery located in? Branch of?
- superior mediastinum
- arch of aorta
3 branches of the arch of aorta:
- brachiocephalic trunk
- left common carotid artery
- left subclavian artery
Visceral Structures: Oesophagus(5):
- superior mediastinum
- muscular tube
- runs from the pharynx to the stomach
- midline
- beginning of arch, moves to the left,
behind left main bronchus
Root of the lung is
a collection of structures that suspend the lungs from the mediastinum
Each root of the lung comprises of (6):
- bronchus
- pulmonary artery
- pulmonary veins
- bronchial arteries
- pulmonary plexus of nerves
- lymphatics
Relations of the root of the right lung to the mediastinum
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What is the relation of the right subclavian artery to the right lung?
The right subclavian artery arches over and is related to the superior lobe of the right lung as it passes over the dome of the cervical pleura and into the axilla (superior mediastinum)
What is the relation of the right subclavian vein to the right lung?
The right subclavian vein arches over and is related to the superior lobe of the right lung as it passes over the dome of the cervical pleura and into the axilla (superior mediastinum)
The —— surface of the right lung lies adjacent to a number of important structures in the mediastinum and the root of the neck (1)(5):
- medial surface of the right lung
- heart
- inferior vena cava
- superior vena cava
- azygous vein
- oesophagus
Relations of the Left Lung Root to the mediastinum:
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What is the relation of the left subclavian artery to the left lung?
arches over and is related to the superior lobe of the left dome as it passes over the dome of cervical pleura and into the axilla (superior mediastinum)
What is the relation of the left subclavian vein to the left lung?
arches over and is related to the superior lobe of the left lung as it passes over the dome of cervical pleura and into the axilla (superior mediastinum)
Major structure of the superior mediastinum related to the ——- surface of the left lung (1)(7):
- the heart (left ventricle)
- aortic arch
- descending thoracic aorta
- oesophagus
- left subclavian artery
- left subclavian vein
The —– position of the right main bronchus result in it being
- vertical
- most common site for inhaled foreign bodies
CT scan of main bronchi position
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Thoracic duct:
- mediastinum
- is
- transports
- from to
- drains where into where
- receives
- passes through the superior and posterior mediastinum
- transports lymph to the venous system
- from abdomen into chest
- drains posterior and superior mediastinum
- drains into the confluence of the left subclavian vein and the left internal jugular vein = left venous angle
- receives multiple branches throughout the thorax
Oesophagus passes through which part of the mediastinum?
- superior and posterior mediastinum
Thoracic duct label on diagram
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What occurs at the transthoracic plane?
- origin and end of aortic arch
- bifurcation of the trachea
- at sternal angle T4/T5b
phrenic nerve pneumonic
C3,4,5 keeps the diaphragm alive
phrenic nerve diagram
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vagus nerve diagram
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The trachea is a very static structure.
True or False?
False
Mobile structure
Moves when swallowing
Trachea and Oesophagus diagram
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Root of the lung diagram
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Relation of right lung root abbreviation to remember anterior structures and where does the oesophagus lie?
Anteriorly: veins artery bronchus
VAB
oesophagus lies directly behind the root of the lung
Thoracic duct:
- mediastinum
- is
- transports
- receives
- passes through the superior and posterior mediastinum
- transports lymph to the venous system
- from abdomen into chest
- in superior mediastinum drains both posterior and superior aspect into the confluence of the left subclavian and left internal jugular vein = venous angle?
- receives multiple branches throughout the thorax
Anterior mediastinum diagram
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just the blue
Boundaries of the anterior mediastinum (5):
- Laterally: mediastinal pleura (part of
parietal pleural membrane) (2
pleura with space so lung can
move within) - Anteriorly: body of sternum and the
transversus thoracis muscles - Posteriorly: pericardium
- Superiorly: continuous with the superior
mediastinum at the level of the
sternal angle - Inferiorly: diaphragm
Thymus gland and the mediastinum location
- immediately deep to the sternum in the superior and anterior mediastinum
Thymus gland is responsible for
- lymphoid organ responsible for T lymphocyte maturation
Thymus gland: Lymph drains from
parasternal, brachiocephalic and tracheobronchial nodes
Thymus gland is supplied with oxygenated blood by
the internal thoracic arteries
Thymus gland after puberty
atrophies and is replaced with fat
The thymus produces and secretes ——, a hormone that
- thymosin
- stimulates T cell production
Boundaries of the posterior mediastinum
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Boundaries of the posterior mediastinum (5):
- anteriorly: posterior pericardium
- posteriorly: vertebrae T5-T12
- Laterally: mediastinal pleura (part of the
parietal pleural membrane) - Superiorly: transverse thoracic plane T4/T5
- Inferiorly: diaphragm
Boundaries of the posterior mediastinum (5):
- anteriorly: posterior pericardium
- posteriorly: vertebrae T5-T12
- Laterally: mediastinal pleura (part of the
parietal pleural membrane) - Superiorly: transverse thoracic plane T4/T5
- Inferiorly: diaphragm
Contents of the posterior mediastinum (7):
Vessels:
- thoracic aorta
- azygous system of veins
Nerves:
- vagus nerve
- sympathetic trunk
- splanchinic nerves
Visceral Structures:
- oesophagus
- thoracic duct
Thoracic Aorta:
- which part of the mediastinum
- location
- oesophagus lies to the
- terminates at
- on right hand side
- posterior mediastinum
- descends on the left side of vertebrae T5-
T12 - oesophagus lies to its right
- terminates at T12 to enter the abdomen
through the aortic hiatus in the diaphragm - thoracic duct and azygous veins ascend on
the right hand side
Name the branches of the thoracic aorta (6):
- 9 pairs of posterior intercostal (inferior)
- subcostal artery
- bronchial (usually paired)
- pericardial
- oesophageal
- superior phrenic artery
Branches of the thoracic aorta diagram
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The supreme intercostal artery originates from
the costocervical trunk, which originates from the subclavian artery
Azygous vein:
- which part of mediastinum?
- location?
- the azygous vein arches over …
- what drains into the azygous vein on the right
side? - what drains into the azygous vein from the left
side?
- posterior mediastinum
- located ascending to the right side of the thoracic
vertebra - arches over the root of the right lung to join the
superior vena cava - posterior intercostal veins, bronchial veins and
the vertebral venous plexus drain into it - the hemiazygous and accessory hemiazygous
veins drains the left side of thorax and drains
into azygous
Hemi-azygous veins:
- which part of the mediastinum?
- ascends on the
- location of accessory hemi-azygous vein and what
does it drain? - location of hemi-azygous vein and what does it
drains? - both drain into
- posterior mediastinum
- ascends on the left side, posterior to the aorta
- accessory hemi-azygous vein drains the posterior
intercostal veins T5-T8 - hemi-azygous vein drains the posterior intercostal
veins T9-T11 - both drain into the azygous vein separately
Insert FHD diagram of azygous system
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CT scan
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Vagus Nerve: posterior mediasteinum:
- originates
- enters
- continues
- contributes
- what supply?
- both right and left originate from the medulla
- enters the superior mediastinum medial to the
phrenic nerve and posterior to the sterno-
clavicular joint - continues into the posterior mediastinum
- contributes to pulmonary, cardiac and
oesophageal plexus - parasympathetic supply
Vagus Nerve posterior mediastinum diagram:
Which part of the mediasteinum?
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Name the structures highlighted
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Right mediastinum diagram
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Left mediastinum diagram
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Right Recurrent Laryngeal Nerve (3):
- hooks under the right subclavian artery and ascends between the trachea and oesophagus
- supplies the larynx
- right vagus continues posterior to the right of the
trachea, posterior to the right brachiocephalic
vein and right lung root
Left Recurrent Laryngeal Nerve (3):
- hooks inferiorly to the aortic arch, immediately
lateral to ligamentum arteriosum - ascends in groove between oesophagus and
trachea - rest of the left vagus nerve runs posteriorly to the
lung root to the oesophageal plexus
Sympathetic Trunk:
- which part of the mediastinum?
- is and located
- passes
- carries
- posterior mediastinum
- vertical chain of sympathetic nerves running on
either side of the vertebral column - sympathetic fibers pass to the pulmonary, cardiac
and oesophageal plexus - afferent fibers carrying sensory information from
the thoracic viscera
Superficial Cardiac Plexus diagram
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deep cardiac plexus diagram
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Oesophagus: Posterior mediastinum:
- descends from
- passes
- veers sligtly
- pierces
- three constrictions
- innervation
- descends from superior mediastinum posterior to
the trachea - passes posterior to the right of the aorta and
posterior to the left atrium - veers slightly left before
- piercing the oesophageal hiatus of the diaphragm
at T10, lying anterior to the abdominal aorta - constricted by: arch of aorta, left main bronchus,
diaphragm - innervated by vagus and sympathetic trunk via
the oesophageal plexus
Oesophagus diagram
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Thoracic Duct: Posterior Mediastinum:
- originates in the cisterna chyli in the abdomen L2
- ascends through the aortic hiatus passing
anterior to the thoracic vertebrae - ascends into the superior mediastinum and
drains into the left venous angle - junction of the left internal jugular and subclavian
veins
Thoracic duct diagram
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Lymph drainage of the body diagram
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Why can lung cancer cause a horse voice?
- lymph node enlargement due to lung
cancer - puts pressure on the LEFT recurrent laryngeal nerve
When you cough what happens?
- vocal cords come together
- pressure in trachea
- vocal cord movement controlled by recurrent laryngeal nerves
Left Recurrent Laryngeal Nerve diagram
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Right Recurrent Laryngeal Nerve diagram
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Superficial cardiac plexus lies on
the arch of the aorta
Deep cardiac pleura lies on
bifurcation of the trachea
Splanchnic Nerves:
- greater splanchnic nerves arise from the
sympathetic trunk and paravertebral
ganglia at levels T5-T9 - lesser splanchnic nerves arise from T10-
T11 - least splanchnic nerves arise from T12
