Lungs, pleura, and pericardium (Morgan R and lecture slides)

What is the thoracic cavity?

space enclosed by thoracic wall and diaphragm

What structures compose the thoracic cavity?

sternum, ribs, thoracic vertebrae, diaphragm

What are the 3 components of the thoracic cavity?

- 2 pulmonary cavities (lungs and pleura, 2 lateral compartments)

- mediastinum (all other thoracic structures, central compartment)

What are the basic structures of the sternum?

manubrium, body, xiphoid proces, jugular notch (suprasternal), and sternal angle (angle of Louis)

What separates the pleural cavities in the thoracic cavity?

the mediastinum

Where does the sternal angle (angle of Louis) articulate?

at the 2nd rib

Why is the sternal angle a good anatomical landmark?

it separates the superior and inferior mediastinum, it is the level of trachea bifurcation, and it is the level where the aortic arch begins & ends

Describe the spinous process of thoracic vertebrae

long, inferiorly sloping spinous processes

Where does the head of the rib articulate with the thoracic vertebrae?

at the superior demifacet (on the vertebral body)

Where does the tubercle of the rib articulate with the thoracic vertebrae?

on the transverse process (facet for tubercule of rib)

Describe how the rib head articulates with the thoracic vertebrae.

The rib head articulates with the vertebral body of 2 thoracic vertebrae, specifically at the demifacets. The superior demifacet is for the vertebra of the same rib number, and the inferior demifacet is for the number of the vertebra above.

Ex: the head of rib 6 would articulate with the inferior demifacet of T5 and the superior demifacet of T6

What are the general boney parts of the rib?

the head, neck, tubercle, angle, body, and costal groove

Where does the tubercle of the rib articulate with the thoracic vertebra?

at the transverse process

Where is the intercostal VAN found?

in the costal groove (area formed between the internal intercostal muscle and innermost intercostal muscle)

What are the muscles of the thoracic cavity?

diaphragm, transverse thoracis, and intercostal muscles (external, internal, and innermost)

What nerve innervates the diaphragm?

the phrenic nerve (C3, C4, C5)

What nerve innervates the transverse thoracis?

intercostal nerves

What nerve innervates the intercostal muscles?

intercostal nerves

What are the layers of the intercostal muscles?

external, internal, innermost

What replaces the external intercostals anteriorly?

external intercostal membrane

What directions do the fibers of the external intercostals run?

anteriorly, inferiorly, and medially

What nerve innervates the external intercostals?

the intercostal nerves

What landmarks do the external intercostal muscles run from?

from the tubercle of ribs to the costochondral junctions

What landmarks do the internal intercostal muscles run from?

angles of the ribs to the sternum

What replaces the internal intercostals posteriorly?

internal intercostal membrane

What direction do the fibers of the internal intercostal muscle run?

opposite of the external intercostal (posterior, superior, and lateral)

What nerve innervates the internal intercostal muscles?

the intercostal nerves

What direction do the fibers of the innermost intercostals run?

the same as internal intercostals (posterior, superior, and lateral)

What nerve innervates the innermost intercostal muscles?

intercostal nerves

Where is the VAN neurovasculature found in the intercostal muscles?

in the costal groove (between internal and innermost intercostals)

VAN goes in which direction?

superior - inferior (vein, artery, nerve)

What spinal nerve forms the intercostal nerves?

the anterior rami of thoracic spinal nerves T1-T11

Where do the anterior intercostal arteries branch from?

IC space 1-6 are branches of the internal thoracic artery

IC space 7-9 are branches of the musculophrenic artery

Where do the posterior intercostal arteries branch from?

posterior IC arteries in IC spaces 1-2 arise branch from the superior intercostal artery (which branches from the costocervical trunk which branches from the subclavian artery)

posterior IC arteries in IC spaces 3-11 arise from the thoracic aorta

Where do the anterior intercostal veins drain to?

internal thoracic vein

Where do the posterior intercostal veins drain to?

azygos system

The internal thoracic artery branches from where?

the subclavian artery

What does the internal thoracic artery divide into?

musculophrenic artery and superior epigastric arteries

What is the pleura?

a continuous serous membrane that covers the surfaces of the lungs and pulmonary cavities

Which pleural layer lines the thoracic wall and pulmonary cavities?

parietal layer

Which pleural layer covers the lungs?

visceral layer (pulmonary pleura)

What innervates the visceral pleura?

autonomic nervous system

What innervates the parietal pleura?

somatic nervous system

What are the parietal pleura parts?

cervical, costal, diaphragmatic, and mediastinal (named by location)

What is a pleural recess?

a space into which the lungs do not extend

What is the costodiaphragmatic recess?

a reflection between the costal and diaphragmatic parietal pleura near the base of the lung

What is the costomediastinal recess?

a reflection between the costal and mediastinal parietal pleura meet (near the thoracic cavity midline)

Where is fluid drawn from for thoracocentesis?

the costodiaphragmatic pleaural recess

Explain the how blood is supplied to the anterior intercostal arteries.

The subclavian artery branches into the internal thoracic artery, which runs down the chest wall. As the internal thoracic artery runs inferiorly, it branches horizontally into the anterior intercostal arteries. That internal thoracic artery supplies the intercostal spaces 1-6, and then it later branches into the musculophrenic and superior epigastric arteries. The musculophrenic artery continues to branch off horizontally and supply the subsequent intercostal spaces 7-9.

What arteries supply the posterior intercostal arteries?

the superior intercostal artery (branch of costocervical trunk) supplies posterior intercostal arteries of intercostal spaces 1-2

the thoracic aorta supplies the posterior intercostal arteries of intercostal spaces 3-11

What does the internal thoracic artery branch into going down the chest wall?

musculophrenic artery and superior epigastric artery

How many lobes does the right lung have?

3 lobes (superior, middle, inferior)

How many lobes does the left lung have?

2 (superior and inferior)

What fissure(s) separate the right lung?

the horizontal fissure separates the superior and middle lobes; the oblique fissure separates the middle and inferior lobes

What fissure(s) separate the left lung?

the oblique fissure separates the superior and inferior lobes

Where is the lingula found?

superior lobe of left lung

What features of the left lung are unique?

the cardiac notch and lingula (superior lobe)

What are the 2 surfaces of the lung?

costal surface (related to thoracic wall) and medial surface (related to the heart)

What shape are the lungs?

conical

Where does the oblique fissure run?

T2 to the 6th rib

Where does the horizontal fissure run?

4th rib (right lung)

What are the grooves/impressions on the right lung?

groove for arch of azygous vein, groove for superior vena cava, groove for brachiocephalic vein, cardiac impression, and groove for esophagus

What heart chamber rests on the cardiac impression of the right lung?

the right atrium

What are the grooves and impressions of the left lung?

groove for subclavian artery, groove for arch of aorta, groove for thoracic (descending) aorta, cardiac impression

What heart chamber rests on the cardiac impression of the left lung?

left ventricle

Which rib do the lungs stop at anteriorly?

6th rib

Which rib do the lungs stop at posteriorly?

rib 10

What is the hilum?

the doorway from the mediastinum to the lung, where structures come into and out of the lung

What is the difference between the lung root and the lung hilum?

the lung hilum is the specific area where structures come into and out of the lung. The root is the collection of structures that connect the lung to the mediastinum (bronchus, pulmonary arteries, pulmonary veins, bronchial arteries, lymphatics)

What structures are in the root of the lung?

bronchus, pulmonary artery, pulmonary vein, bronchial arteries, lymphatics (bronchiopulmonary or hilar lymph nodes), and the pulmonary ligament

What type of blood do pulmonary arteries carry?

deoxygenated blood

What type of blood do pulmonary veins carry?

oxygenated

What is unique about the bronchi of the right lung?

there is a bronchus above the pulmonary artery that is not seen in the left lung

The pulmonary artery is above the bronchus in the root of the lung. Which lung is it?

the left lung- the right lung has a bronchus above the pulmonary artery

What anatomical direction is the position of the bronchus in the right lung?

posterior

What is the direction of the pulmonary artery in the right lung in relation to the bronchus?

anterior to bronchus

What direction is the pulmonary vein in the right lung in relation to the bronchus?

inferior and anterior to bronchus

What position is the bronchus in the right lung?

posterior

What position is the pulmonary artery in the left lung in relation to the bronchus?

superior to bronchus

What direction is the pulmonary vein in the left lung in relation to the bronchus?

inferior and anterior to bronchus

What is the pulmonary ligament?

- Fold of pleural membrane below the the root

- Attaches lung to mediastinum

Where is the vagus nerve in relation to the lung?

posterior to the root of the lung

Where is the phrenic nerve in relation to the lung?

anterior to the root of the lung

What is the name of the bronchus that is superior to the artery in the right lung?

eparterial bronchus (aka superior lobar bronchus)

Where does the trachea begin and end?

begins inferior to the larynx and ends at the sternal angle (T4-T5)

What does the trachea divide into?

right and left primary bronchi

What is the breakdown of the bronchus past the primary level in the right lung?

From primary bronchus it splits into secondary bronchi into the superior (eparterial), middle, and inferior lobes

What is the breakdown of the bronchus past the primary level in the left lung?

From the primary bronchus it splits into the seconday lobar bronchi into the superior and inferior lobes

What is the carina?

cartilaginous ridge on the internal surface of the trachea where it bifurcates into the right and left primary bronchus

What covers the trachea?

c-shaped cartilaginous rings that are incomplete posteriorly

Where is the transversus thoracis muscle found?

on the internal surface of the anterior chest wall

What nerve innervates the diaphragm?

Phrenic nerve (C3, C4, C5 keeps the diaphragm alive)

The musculophrenic artery is a branch of which artery?

the internal thoracic artery (which branches from the subclavian artery)

What innervates the visceral layer of the pleura?

autonomic nervous system

What innervates the parietal layer of the pleura?

somatic nervous system

What are the divisions the parietal pleura is divided into?

costal, diaphragmatic, cervical, and mediastinal

What is the pleural cavity?

the space between the visceral and parietal pleura (contains fluid)

Are the right and left pleural cavities of the lungs connected?

no

Do the lungs lie within the pleural cavity?

No