Bronchi, Pleura, lungs and diaphragm

Question 1

What is the sternal angle?

Answer 1

the point at which the second costal cartilage attaches to the joint between the manubrium and the sternum. However, it is T4/T5

Question 2

Where is there a discrepancy?

Answer 2

There is a discrepancy between the rib numbers and the vertebral levels, as the ribs slops downwards

Question 3

What is the vertebra prominens?

Answer 3

C7, as it is most prominent on the neck, you can feel it at the back of the neck.

Question 4

Where is the trachea?

Answer 4

Extends from vertebral level C6 to T4/5 which is the manubrium joint or the angle of louis.
Held open by C-shaped cartilage rings, which are open posteriorly
Lowest ring has a hook – carina (keel of ship): the bifurcation of left and right main bronchus

Question 5

where is the primary bronchi located and what is the difference between them in terms of appearance?

Answer 5

Formed at T4/5

Right wider and more vertical than left

Question 6

what does the lobar (secondary) bronchi supply?

Answer 6

• Formed withing the lungs
• supply the lobes of the lungs.
• 3 lobes on the right lung and 2 on the left, therefore more lobar bronchi on the right than left.

Question 7

What does the Segmental (tertiary) bronchi supply and how mnay are there in each lung?

Answer 7

Supply the bronchopulmonary segments ( these supply independent units of lung tissue)

• SAME number 10 in each lung
• are functionally independent, so removal of it won’t affect anything upstream, it has its own blood supply, airway.

Question 8

where can you do an emergency incision if airway is blocked from the face due to trauma or blood?

Answer 8

Anatomy:
Thyroid cartilage- this is where the Adams apply
Median cricothyroid ligament: very important in an emergency situation as a professional can make a hole to allow breathing. Lacks cartilage- hole

Cricoid cartilage
Trachea, making a hole in the trachea is a surgery procedure which will happen in the hospital

Question 9

where are the lungs located?

Answer 9

• it is in the thorax
• separated from each other by heart and other contents of the mediastinum
• Each lies freely in its pleural cavity - apart from its attachment to the heart (via pulmonary vessels) and trachea at the lung root (hilum)

Question 10

what colours are arteries and pulmonary arteries?

Answer 10

Arteries of the systemic circulation= RED

Pulmonary arteries = Blue

Question 11

what are the vessels of the heart

Answer 11

Coming back to the heart:

• superior vena cava
• this is formed by 2 big veins: brachiocephalic veins ( 2 main vessels bringing blood back from the upper limbs and the head which join and form the superior vena cava).

Aortic arch- 3 vessels coming out:

• left/right common carotid artery
• right/left subclavian artery
• brachiocephalic artery

Pulmonary artery from right and left of the lungs.

Question 12

what is the shape of the lungs?

Answer 12

Conical in shape.
APEX:
-thoracic inlet oblique: apex rises 3-4 cm above
level of first costal cartilage

BASE:

• concave
• rests on convex surface of diaphragm

3 borders - (edges) - anterior, posterior, inferior
3 surfaces - costal, medial (mediastinal), inferior (diaphragmatic)

Diaphragm separates
right lung from right lobe of liver
left lung from left lobe of the liver, stomach & spleen

Question 13

What are the general features of the mediastinal surface of lung?

Answer 13

This is how it looks when you open the chest.

• Posterior part in contact with thoracic vertebrae: VERY THICK of tissue
• Anterior part - deeply concave - accommodates the heart - cardiac impression larger on L than R because of position of heart

-Above and behind cardiac impression - hilum of the lung: (this is the reflection of pleural cavity which is called the visceral plura) where vessels, bronchi & nerves enter & leave the mediastinum
Hilum is the pleural reflection
Root is the stuff going to the heart.

-you have 2 pulmonary veins coming from the right and 2 pulmonary veins coming from the left lung, so you can see 4 holes at the back of the heart.

Question 14

What are the specific features of the left lung?

Answer 14

• Has a lingula: like a tongue, projects a bit forwards and towards the heart
• there are also indentations and grooves
• big cardiac impression (groove)

Two lobes:
Superior
Inferior
separated by oblique fissure

Superior lobe lies above the fissure – includes:
Apex
Most of anterior part of lung
-left lung has a groove for the aorta.

Question 15

what are some specific features of the right lung?

Answer 15

• has grooves from main artery and for the superior vena cava
• right lung has main grooves for the oesophagus and the superior vena cava

Three lobes:
superior
middle
inferior

Separated by 2 fissures
oblique fissure - separates inferior lobe from the other 2 lobes
horizontal fissure - separates superior from middle lobe

The right lung is slightly larger than the left due to the presence of the heart.

Question 16

Similariteis between right and left lung?

Answer 16

• Both mediastinal surfaces have grooves

- Most anterior near the apex have grooves

Question 17

What is the root (hilum) of the lung?

Answer 17

Connects mediastinal surface to heart and trachea
formed by structures that enter or leave hilum:
Principal (primary) bronchus
Pulmonary artery (deoxygenated blood from RV)
2 pulmonary veins (oxygenated blood to LA)
Bronchial arteries (oxygenated blood from descending aorta) and veins
Pulmonary plexus of nerves (autonomic)
Lymph vessels and nodes
all enveloped in pleura

Question 18

what is the pulmonary trunk?

Answer 18

Pulmonary trunk: emerging from the right ventricle, goes superiorly and posterioly where it divides into 2, right and left artery.

Question 19

what happens to the pleura during breathing?

Answer 19

• Pleural cavity is expanded by muscles in walls

- Elastic lungs expand with the pleural cavity, sucking air down trachea and bronchi into lungs

Question 20

What changes happens in the diaphragm when breathing?

Answer 20

Contraction of the diaphragm increases the vertical dimension of the thoracic cavity.
When it contracts, the diaphragm presses on the abdominal viscera which initially descend (because of relaxation of the abdominal wall during inspiration)
Further descent is stopped by the abdominal viscera, so more diaphragm contraction raises the costal margin
Increased thoracic capacity produced by diaphragm and rib movements in inspiration, reduces intrapleural pressure, with entry of air through respiratory passages and expansion of the lungs

Question 21

where is the diaphragm located?

Answer 21

The margin of the diaphragm (black) is attached to the:
costal margin (lower border of the rib cage)
xiphoid process
ends of ribs 11 and 12
lumbar vertebrae

Question 22

where is the diaphragm when we breath in?

Answer 22

The dome of the diaphragm (red) bulges high inside the rib cage.
So high abdominal organs such as liver are covered by diaphragm, pleura and lung

Question 23

Ribs in breathing

Answer 23

Ribs elevated - anterior ends thrust forward and upwards - increases antero-posterior dimension of thoracic cavity.

At same time ribs are everted, increasing transverse diameter of thoracic cavity

Internal and external intercostal muscles stiffen the rib cage to increase efficiency of diaphragm

Question 24

forced expiration/

Answer 24

In deep or forced expiration, this is assisted by the muscles of the abdominal walls that squeeze the abdominal organs against the diaphragm and pull the lower ribs downward