The Respiratory System

Question 1

What is the thoracic inlet bounded by?

Answer 1

T1 posteriorly.
The 1st pair of ribs laterally.
The costal cartilage of rib 1 and the superior border of the manubrium anteriorly.

Question 2

What is the thoracic outlet bounded by?

Answer 2

T12 posteriorly.
The 11th and 12th pairs of ribs laterally.
The costal cartilages of ribs 7-10 and the xiphisternal joint anteriorly.

Question 3

Where is the sternum, and the sternal angle, located?

Answer 3

Sternum - lower border of T4.
Sternal angle - T5.

Question 4

Describe the shape of the 1st rib.

Answer 4

Broad and flat.
Its surfaces look up and down.
Head - one articular facet, for the body of T1.

Question 5

Describe the upper surface of the body of the 1st rib.

Answer 5

Marked by two shallow grooves, separated by the scalene tubercle (for attachment of the anterior scalene muscle).

Question 6

What do the two grooves of the 1st rib lodge?

Answer 6

The anterior groove lodges the subclavian vein.
The posterior groove lodges the subclavian artery and the lowest trunk of the brachial plexus.

Question 7

Describe the general features of a typical rib.

Answer 7

Head - two articular facets.
A costal groove.
A tubercle.

Question 8

What are costovertebral joints?

Answer 8

The head of the rib articulates with the body of the thoracic vertebra of the same number, and the body of the vertebra above.

Question 9

What are costotransverse joints?

Answer 9

The tubercle of the rib articulates with the transverse process of the thoracic vertebra of the same number.

Question 10

What are the attachments of the diaphragm?

Answer 10

Peripherally at the lumbar vertebrae, arcuate ligaments, costal cartilages of ribs 7-12, and xiphoid process of the sternum.
Centrally at the central tendon.

Question 11

What are the crura of the diaphragm?

Answer 11

Arises from the vertebrae.
Tendinous in structure.

Right crus - arises from L1-L3.
Left crus - arises from L1-L2 and their intervertebral discs.

Question 12

What is the caval opening?

Answer 12

A diaphragmatic hiatus at T8.
Goes through the central tendon.
Transmits the inferior vena cava and the right phrenic nerve.

Question 13

What is the oesophageal opening?

Answer 13

A diaphragmatic hiatus at T10.
Located through the muscular sling of the right crus.
Transmits the oesophagus and both vagus nerves.

Question 14

What surrounds the oesophageal opening?

Answer 14

Fibres of the right crus help prevent the reflux of gastric contents back into the oesophagus.

Question 15

What is the aortic opening?

Answer 15

A diaphragmatic hiatus at T12.
Located between the left and right crus.
Transmits the aorta, azygos vein, hemiazygos vein, and the thoracic duct.

Question 16

Where are the roots of the phrenic nerve?

Answer 16

Found in the anterior rami of C3-C5.
Mainly C4 - both motor and sensory.

Question 17

What does the phrenic nerve innervate?

Answer 17

Pierces and innervates the diaphragm interiorly via motor neurons.
Supplies the central part of the diaphragm via sensory neurons.

Question 18

What innervates the peripheral portions of the diaphragm?

Answer 18

Sensory fibres of intercostal nerves.
T7-T12.

Question 19

What are the different intercostal muscles?

Answer 19

External - /// (right).
Internal - \\ (right).
Innermost - vertical.

Question 20

What is the arterial supply of the thoracic wall?

Answer 20

Posterior intercostal arteries (branch of mainly descending thoracic aorta).
Anterior intercostal arteries (branch of internal thoracic artery).
Branches of axillary arteries.

Question 21

What is the venous drainage of the thoracic wall?

Answer 21

The azygos vein, accessory hemiazygos vein, and hemiazygos vein.
Internal thoracic veins.

Question 22

Where does the left side of the chest wall drain to?

Answer 22

The thoracic duct and left subclavian vein.

Question 23

Where does the right side of the chest wall drain to?

Answer 23

The right lymphatic duct and right subclavian vein.

Question 24

Where does the breast drain to?

Answer 24

The axillary, parasternal, and abdominal lymph nodes.

Question 25

What can damage to the phrenic nerve cause?

Answer 25

Diaphragm weakness or paralysis.
Gas exchange is affected.