Intro to Lungs and Pleura

Question 1

what are the 3 bones of the sternum?

Answer 1

manubrium
body
xyphoid process

Question 2

at what rib is the sternal angle or manubriosternal junction found?

Answer 2

2nd rib

Question 3

which ribs articulate with the sternum? what about the rest?

Answer 3

ribs 1-7 articulate with the sternum

ribs 8-10 articulate with the rib above it

ribs 11 and 12 are “floating ribs” and do not articulate anteriorly

Question 4

which artery runs on the inner surface of the costal cartilages just beside the sternum? where does it arise from?

Answer 4

internal thoracic artery - arises from subclavian artery

from it, an intercostal artery branches at each rib level

Question 5

where do ribs articulate posteriorly?

Answer 5

except for first rib, all rib tubercles articulate posteriorly at the transverse process of the vertebral body

Question 6

where do the intercostal nerves originate from?

Answer 6

the anterior ramus of thoracic spinal nerves are the intercostal nerves

Question 7

T/F: intercostal arteries, veins, and nerves supply the entire thickness of the chest wall

Answer 7

TRUE: including intercostal muscles, ribs, skin, parietal pleura

Question 8

what is the lung pleura made of, and what is its function?

Answer 8

pleura: serous membrane lined by simple squamous secretory epithelium (mesothelium)

lines external surface of the lung, internal surface of chest wall, superior surface of diaphragm, and lateral surface of mediastinum

encloses potential space (pleural cavity) containing pleural fluid that provides lubrication

surface tension of the pleural fluid keeps the lung expanded and elastic recoil of the lung results in a negative pressure in the pleural space

Question 9

visceral vs parietal pleural of the lung

Answer 9

the pleura is continuous, but the pleural fused to the surface of the lung is visceral pleura

pleura not directly contacting the lung is parietal pleura

reflection occurs at the hilus of the lung, which surrounds the root of the lung

Question 10

what structures make up the root of the lungs, which pass through the hilum (reflection point of visceral and parietal pleura)?

Answer 10

bronchus, pulm artery, pulm veins, bronchial arteries, bronchial veins, nerves, lymphatics

Question 11

the costodiaphragmatic recess is formed by the reflection of…

why is this space clinically significant?

Answer 11

the costodiaphragmatic recess is formed by the reflection of costal pleura to diaphragmatic pleura

excess fluid in the pleural cavity can be found in the costodiaphragmatic recess, because that is the lowest space - this is where fluid may be tapped by thoracentesis without puncturing the lung

Question 12

where is the bottom of the lung and the bottom of the pleura, respectively, at the following locations:
a. midclavicular line
b. midaxillary line
c. paravertebral line

Answer 12

a. midclavicular line: bottom of lung is at 6th rib, bottom of pleura is at 8th rib

b. midaxillary line: 8th (lung) and 10th (pleura)

c. paravertebral line: 10th (lung) and 12th (pleura)

Question 13

thoracentesis

Answer 13

tapping into the costodiaphragmatic recess with a needle

pass through middle of intercostal space to avoid intercostal neuro-vascular structures

Question 14

which lung is at a higher risk of a foreign body entering into it?

Answer 14

the right main bronchus is wider and more vertical than the left - foreign bodies are more likely to enter the right main bronchus, and more likely to enter the right lower lobe

Question 15

what causes pneumothorax?

Answer 15

a penetrating wound in the chest wall or some other cause that results in abnormal communication between the pleural cavity and atmospheric pressure

this allows air to follow the pressure gradient and enter the pleural cavity, and the lung collapses (elastic recoil and surface tension is gone)

pneumothorax = air in the pleural cavity, which results in a collapsed lung

*note that this causes a mediastinal shift to the contralateral lung