Unit 5: Thoracic cavity and mediastinum

What are the thoracic apertures?

superior thoracic aperture
inferior thoracic aperture

What is the superior thoracic aperture bounded by?

first thoracic vertebra
first pair of ribs
top of sternum

What is the inferior thoracic aperture bounded by?

12th TV
12th ribs
anterior extremities of the 11th ribs
costal cartilages of teh 10th, 9th, 8th, and 7th ribs
xiphoid process

What encloses left and right sides of the cavity?

The pleura

What is the mediastinum?

a thick parition of tissue and structures between the lungs (between the left and right mediastinum)

What structures make up the mediastinum?

thymus
heart and its pericardium
great vessels
trachea and primary bronchi
esophagus
neerves and lymphatics

What encloses the lungs?

a double layer of pleura

What is the outer layer of the pleura called?

parietal pleura

How big is the parietal pleura?

large enough to allow the lung to expand

What are the parts of the parietal pleura?

costal
diaphragmatic
cervical
mediastinal

What innervates the parietal pleura?

sensory fibers from:
intercostal nerves
phrenic nerve

What are the reflections of the parietal pleura?

costomedistinal refection
costodiaphragmatic reflection

What is the costomedistinal refection?

a junction of costal and mediastinal portions

What does the costomedistinal refection contain?

costomediastinal recess

What is the costodiaphragmatic refection?

junction of the costal and diaphragmatic portions

What does the costodiaphragmatic refection contain?

costodiaphragmatic recess
the long does NOT extend into during quiet breathing

What is the inner layer of the pleura?

visceral pleura

Where is the visceral pleura?

fused to the lung to form its outer surface

What is a pleural cavity?

a serious cavity seperated by the visceral and parietal pleura

Where are the parietal and visceral pleura continuous?

at the root of the lung and pulmonary ligament

What is the root of the lung?

a short tubular collection of structures that together attach the lung to structures in the mediastinum

What is the pulmonary ligament?

a thin, blade-like fold of pleura projects inferiorly from the root of the lung and extends from the hilum to the mediastinum

Where does the mediastinum extend from?

the superior thoracic aperature above to the diaphragm below
from the sternum in front to the vertebral column posteriorly and between the mediastinal pleura of the two sides

What is the mediastinum divided into?

superior and inferior mediastinum

What divides the mediastinum into the superior and inferior mediastinum?

a horizontal plane extending through the sternal angle anteriorly and the disk between TV4 and TV5

What is the inferior mediastinum further subdivided into?

anterior
middle
posterior

What does the middle inferior mediastinum contain?

the heart
pericardial sac
roots of the greater vessels

What is in the superior mediastinum? anterior to posterior

thymus
brachiocephalic veins and superior vena cava
aortic arch
trachea
esophagus
thoracic duct
phrenic nerves
vagus nerves

What is the thymus?

the most anterior structure of the superior mediastinum
largely replaced by fat

What is the shape of the thymus?

bilobed

What is the blood supply to the thymus?

pericardiacophrenic vessel

How/where are the brachiocephalic veins forms?

by the confluence of the subclavian and internal jugular veins at the root of the neck

Is the right brachiocephalic vein horizontal or verticle?

verticle

Is the right or left brachiocephalic vein longer?

left

What is the course of the left brachiocephalic vein?

oblique and crossses the branches of the aortic arch

Where is the superior vena cava?

it continues the vertical course of the right brachiocephalic vein
receives the azygos vein before entering the pericardial sac

Where is the aortic arch?

it starts anterior and arches backward over the left primary bronchus

What is the ligamentum arteriosus connected to?

the inferior surface of arch to the left pulmonary artery

What is the first branch of the aortic arch?

brachiocephalic trunk

Where is the brachiocephalic trunk?

ascends in front of the trachea to its right side

What does the brachiocephalic trunk divide into?

right subclavian and right common carotid artery

What are the branches of the aortic trunk?

brachiocephalic trunk
right subclavian
left subclavian
right common carotid artery
left common carotid

Where is the left common carotid?

arise independently from the arch and run more or less vertically along the left side of the trachea

Where is the trachea?

behind the great vessels and immediately anterior to the esphagus

What is the most posterior structure of the mediastinum?

esophagus

Where is the thoracic duct?

left side of the esophagus and vertebral column

How does the thoracic duct get to its junction? What is the junction of the thoracic duct?

arches over subclavian artery from behind to reach the left subclavian vein at its junction
juntion: with the internal jugular vein

Where are the phrenic nerves? C3-5

pass anterior to both subclavian arteries and root of the lung, then between the pericardium and mediastinal pleura to reach the diaphragm

Where is the right phrenic nerve?

it runs on the lateral side of the great veins

What are the great veins?

brachiocephalic
superior vena cava
inferior vena cava

Where is the left phrenic nerve?

runs antero-lateral to the left common carotid artery and aortic arch

Where is the vagus nerve?

passes anterior to subclavian arteries and run posterior to the root of the lung

Where is the right vagus nerve?

lateral to the trachea

Where does the right recurrent laryngeal nerve pass?

under the right subclavian artery and then ascends to the larynx

Where is the left vagus nerve?

between the left common carotid and subclavian arteries and lateral to the aortic arch?

Where does the left recurrent laryngeal nerve pass?

under the aortic arch immediately to the left of the ligamentum arteriosus to ascend in the groove between trachea and esophagus

Where do the cardiac nerves descend from?

the cervical symphatic trunk and vagus nerve to reach the cardiac plexuses around aortic arch

What is in the anterior mediastinum?

some fat, connective tissue

What is the lowest extension of the thymus and some lymph nodes?

anterior mediastinum

What is in the middle mediastinum?

pericardial sac
heart
roots of the great vessels

Where is the pericardial sac?

pericardium

What is the pericardial sac?

double-walled sac that surrounds the hear and roots of the greater vessels

What are the layers of the pericardial sac?

fibrous pericardium
serous pericardium

What is the fibrous pericardium?

a stout external layer of the pericardial sac

What are the parts of the serous pericardium?

parietal and visceral

What is the parietal pericardium?

inner layer of the pericardial sac that is fused to the fibrous pericardium

Where is the visceral pericardium?

It covers the heart

What is the visceral pericardium also known as?

epicardium

Where does teh visceral pericardium reflect from?

the heart and great vessels to become continuous with the parietal pericardium

What does the reflections of the pericardium from the great vessels create?

spaces/sinuses

What are the sinuses of the pericardium?

transverse pericardial sinus
oblique pericardial sinus

Where is the transverse pericardial sinus?

space posterior to ascending aorta and plulmonary trunk and anterior to the superior vena cava

Where is the oblique pericardial sinus?

blind recess on posterior aspect of heart caused by pericardial reflections off the pulmonary veins and inferior vena cava

What are the roots of the great vessels?

pulmonary trunk (right and left)
ascending aorta
superior vena cava
inferior vena cava
right superior and inferior pulmonary veins
left superior and inferior pulmonary veins

What is pericarditis?

the inflamation of the serous pericardium when pericardial fluid accumulates that compresses the atria

What is mediastinitis?

deep infection of the neck that has spread to the thorax