Mediastinum
Mediastinum
The region between the two lungs
Contain heart, blood vessels, trachea, oesophagus..
Important landmarks:
Sternal angle
T12 vertebrae
Ludwig’s plane
Horizontal plane through sternal
angle
Heart at central position at T4
Upper border of sternum at T2
Upper limit of mediastinum at first
rib
Divisions + Borders:
Superior mediastinum
Above Ludwig’s plane (T4/T5)
Superior thoracic aperture as
boundary
Inferior mediastinum
Below Ludwig’s plane
Have subdivisions
Anterior mediastinum
Sternum → pericardial
sac
Mediastinum 1
, Middle mediastinum
Diaphragm as
boundary
Bounded by pericardial
sac
Posterior mediastinum
Thoracic vertebrae +
pericardial sac as
boundary
Building the Mediastinum
1. 12 thoracic vertebrae with
sympathetic trunk
2. Chains of sympathetic ganglia
3. Azygos venous system
a. Begins in the abdomen and
enters the thorax
b. 2 hemiazygos veins join the
azygos vein at T8
c. Azygos vein arches at the
upper end over the right
bronchus and joins the SVC
4. Thoracic duct = a lymphatic
channel
a. Begins in the abdomen from the
cisterna chyli
b. Pass through the superior
aperture of thorax
Mediastinum 2
Mediastinum
The region between the two lungs
Contain heart, blood vessels, trachea, oesophagus..
Important landmarks:
Sternal angle
T12 vertebrae
Ludwig’s plane
Horizontal plane through sternal
angle
Heart at central position at T4
Upper border of sternum at T2
Upper limit of mediastinum at first
rib
Divisions + Borders:
Superior mediastinum
Above Ludwig’s plane (T4/T5)
Superior thoracic aperture as
boundary
Inferior mediastinum
Below Ludwig’s plane
Have subdivisions
Anterior mediastinum
Sternum → pericardial
sac
Mediastinum 1
, Middle mediastinum
Diaphragm as
boundary
Bounded by pericardial
sac
Posterior mediastinum
Thoracic vertebrae +
pericardial sac as
boundary
Building the Mediastinum
1. 12 thoracic vertebrae with
sympathetic trunk
2. Chains of sympathetic ganglia
3. Azygos venous system
a. Begins in the abdomen and
enters the thorax
b. 2 hemiazygos veins join the
azygos vein at T8
c. Azygos vein arches at the
upper end over the right
bronchus and joins the SVC
4. Thoracic duct = a lymphatic
channel
a. Begins in the abdomen from the
cisterna chyli
b. Pass through the superior
aperture of thorax
Mediastinum 2
