Module 3

Superior mediastinum includes

pair or brachiocephalic veins- forming superior vena cava, emptying
into the right ventricle
-thymus is anterior to this, between left brachiocephalic vein and
manubrium of sternum

What is the brachiocephalic vein composed of?

an internal jugular vein and subclavian vein

Which BC vein is longer? Left or right?


What is posterior to both BCs?


Where is the right vagus nerve located?

ebtween superior vena cava and right common carotid artery

Where is the left vagus nerve located?

between left BC vein and left common carotid artery

Where is the aortic arch located?

behind left brachiocephalic vein

Ascending aorta comes out of the


Brachiocephalic trunk/artery comes out of

the right side of aorta and breaks into right common carotid artery
and right subclavian artery

On the left side of aortic arch

there is no trunk connecting left common carotid artery or subclavian artery

On the aortic arch

2 BC veins and 1 BC trunk

What does each vagus nerve carry?

preganglionic parasympathetic and visceral sensory fibers to thoracic
viscera. Gives rise to recurrent laryngeal nerve

Which vagus nerve is longer?


Where is the left vagus nerve located that the right vasus nerve is not?

superior mediastinum, hooks underneath the aortic arch, behind
ligamentum arteriosum.

Where does azygous vein arch over?

right main bronchus

What does aortic arch arch over?

left main bronchus

Where is the trachea located?

behind aorta

Where is the esophagus located?

behind trachea and passes beyond superior mediastinum

Vagus nerves make their way down

heart and lungs with their innervation pattern and then wrap around
esophagus, providing innervation to smooth and skeletal muscle of esophagus

What are the narrow points of the esophagus?

is origin form the pharynx in the neck and at the esophageal hiatus
of the diaphragm

Where is the posterior mediastinum located?

below transverse plane, posterior to the heart, anterior to the vertebrae

What does azygous mean?


Azygous vein

drains much of the intercostal spaces bilaterally

Where do the accessory hemiazygous (3-5) veins and hemiazygous veins
(3-4) drain?

left side of chest wall

Where do the accessory hemiazygous (3-5) veins and hemiazygous veins
(3-4) carry blood?

across midline to azygous vein

Where does left superior intercostal vein drains?

first two veins on the left side

Where does azygous vein return blood?

to superior vena cava

Where does thoracic duct drain all lymph?

below diaphragm and returns everything to the left BC

What does thoracic duct drain lymph from?

abdominal and pelvic viscera, from below the diaphragm and the left
side structures above the diaphragm

What is lymph?

extracellular fluid collected from most parts of the body that drains
into veins at the base of the neck

What does the right lymphatic duct drain?

the right side structures above the diaphragm. Left is longer than
the right

Where does the left lobe of the lung drain fluid?

into the thoracic duct

Lower left lobe fluid

crosses over main bronchi and empties itself into right lymphatic
duct along with entire right lung

Where do anterior intercostal veins drain into?

a pair of internal thoracic veins


made of skeletal muscle. Major muscle of inspiration

When diaphragm contracts

both domes descend and increase the superior to inferior dimension of
the thorax

Diaphragm pulls down

chambers of the heart. Is innervated by a pair of phrenic nerves and
courses through mediastinum

What do phrenic nerves consist of?

ventral rami from C3, 4, and 5

Phrenic and intercostal nerves innervate

pleural membranes that cover it.




sensory both sides of diaphragm

What do the phrenic nerves and intercostal nerves provide?

sensory innervation of the diaphragm

Ribs and sternum move to

anteroposterior and transverse dimensions of thorax.

Pump handle


Bucket handle

transverse dimension

External intercostals and anterior fibers of internal intercostals

elevate ribs and sternum


passive recoil of lungs and rib cage


internal intercostals depress ribs

Abdominal muscles push up

diaphragm; intercostal muscle are innervated by intercostal nerves