Anatomy 2

Question 1

How do you use surface anatomy to determine

• the positions of the lobes of each lung
• the position of the fissures
• the borders of the lungs
• the indent for the mediastinum

Answer 1

Positions of Fissures (Anterior)

• 1. Apices of lungs extend above clavicles approx 2.5cm
• 2.Oblique fissures on both sides: start at T2-T4, 5th interspace laterally, then follows rib 6 anteriorly.
• 3.Horizontal fissure on the right extends from the oblique fissure and follows right 4th rib
• 4. Left lung has large deficit anteriorly extending from 4th to 6th rib and from sternum to costochondral joint - cardiac notch
• 5. Both lungs extend to 8th rib laterally

Question 2

What are the names of the pleural recesses, and where do you find them?

Answer 2

• Costomediastinal recesses
• Anteriorly, a costomediastinal recess occurs on each side where costal pleura is opposed to mediastinal pleura. The largest is on the left side in the region overlying the heart.
• Costodiaphragmatic recesses
• The largest and clinically most important recesses are the costodiaphragmatic recesses. The costodiaphragmatic recesses are the regions between the inferior margin of the lungs and inferior margin of the pleural cavities. They are deepest after forced expiration and shallowest after forced inspiration

Question 3

How would you find the costodiaphragmatic recess using surface anatomy?

Answer 3

• During quiet respiration, the inferior margin of the lung crosses rib 6 in the midclavicular line, rib 8 in the midaxillary line, and then courses somewhat horizontally to reach the vertebral column at vertebral level T10.
• The inferior margin of the pleural cavity at the same points is rib 8, rib 10, and vertebra T12. The costodiaphragmatic recess is the region between the two margins.

Question 4

When are the costodiaphragmatic recesses largest, and when are they smallest?

Answer 4

They are deepest after forced expiration and shallowest after forced inspirations
During expiration, the inferior margin of the lung rises and the costodiaphragmatic recess becomes larger

Question 5

How are the parietal and visceral pleura Innervated?

Answer 5

Parietal Innervation: Intercostal nerves, Phrenic nerve
Visceral Innervation: Pulmonary plexus

Question 6

What is the mediastinum and what does it contain, and what structures pass through it? (6)

Answer 6

The mediastinum is a thick flexible tissue partition in a medial saggital position, it contains the heart. The mediastinum can be accessed surgically without disturbing the pleural cavities.

• Structures that pass through the mediastinum:
• The vagus nerve
• The oesophagus
• The phrenic nerve that supplies the diaphragm
• The trachea
• The thoracic aorta
• The vena cava

Question 7

Describe the surfaces and borders of the lungs

Answer 7

• The base sits on the diaphragm.
• The apex projects above rib I and into the root of the neck
• The two surfaces:
• The costal surface lies immediately adjacent to the ribs and intercostal spaces of the thoracic wall.
• The mediastinal surface lies against the mediastinum anteriorly and the vertebrae posteriorly, contains the hilum of the lung.
• The three borders:
• The inferior border of the lung separates the base from the costal surface.
• The anterior and posterior borders separate the costal surface from the medial surface.
• The anterior and inferior borders are sharp, the posterior border is smooth and rounded.

Question 8

What is in each lung root and located in each hilum? What are the general positions of each structure in relation to the others?

Answer 8

• a pulmonary artery;
• two pulmonary veins;
• a main bronchus;
• bronchial vessels;
• nerves; and
• lymphatics.
• Generally, the pulmonary artery is superior at the hilum, the pulmonary veins are inferior, and the bronchi are somewhat posterior in position.

Question 9

What happens in the right lung root that does not happen in the left lung root?

Answer 9

On the right side, the lobar bronchus to the superior lobe branches from the main bronchus in the root, unlike on the left where it branches within the lung itself, and is superior to the pulmonary artery.

Question 10

When listening for the lobes, after you know their positions from surface anatomy, you will hear most sound from the

• Superior lobe on the…… Surface
• Middle lobe on the……..surface
• Inferior lobe on the……surface

Answer 10

• Superior lobe on the anterior and lateral Surface
• Middle lobe on the anterior and lateral surface
• Inferior lobe on the posterior inferior surface

(Although James said that almost all lung sounds are heard at the back, and that you always compare like for like on each side when checking lung sounds)

Question 11

The medial surface of the right lung lies adjacent to a number of important structures in the mediastinum and the root of the neck. What are they?

Answer 11

The medial surface of the right lung lies adjacent to a number of important structures in the mediastinum and the root of the neck:

• inferior vena cava,
• superior vena cava,
• azygos vein, and
• esophagus.

The right subclavian artery and vein arch over and are related to the superior lobe of the right lung as they pass over the dome of cervical pleura and into the axilla.

Question 12

What part of the left lung extends over the heart bulge?

Answer 12

From the anterior border of the lower part of the superior lobe a tongue-like extension (the lingula of left lung) projects over the heart bulge

Question 13

The medial surface of the left lung lies adjacent to a number of important structures in the mediastinum and root of the neck. What are they?

Answer 13

• heart,
• aortic arch,
• thoracic aorta, and
• esophagus.
• The left subclavian artery and vein arch over and are related to the superior lobe of the left lung as they pass over the dome of cervical pleura and into the axilla.

Question 14

What is a bronchopulmonary segment? How do pulmonary veins tend to relate to them?

Answer 14

• A bronchopulmonary segment is the area of lung supplied by a segmental bronchus and its accompanying pulmonary artery branch.
  Tributaries of the pulmonary vein tend to pass between and around the margins of segments.

Question 15

• How is Each bronchopulmonary segment shaped?
• Surgically, what is important about the bronchopulmonary segment?.
• How many bronchopulmonary segments are there in each lung?

Answer 15

• Each bronchopulmonary segment is shaped like an irregular cone with the apex at the origin of the segmental bronchus and the base projected peripherally onto the surface of the lung.
• A bronchopulmonary segment is the smallest, functionally independent region of a lung and the smallest area of lung that can be isolated and removed without affecting adjacent regions.
• There are ten bronchopulmonary segments in each lung (Fig. 3.44); some of them fuse in the left lung.

Question 16

• Where do the right and left pulmonary arteries originate from?
• What type of blood do they carry, and where to?

Answer 16

The right and left pulmonary arteries originate from the pulmonary trunk and carry deoxygenated blood to the lungs from the right ventricle of the heart.

Question 17

Where does the bifurcation of the pulmonary trunk occur?

Answer 17

The bifurcation of the pulmonary trunk occurs to the left of the midline just inferior to vertebral level T4/5, and anteroinferiorly to the left of the bifurcation of the trachea.

Question 18

How does the right pulmonary artery lie in relation to other structures in the mediastinum?

Answer 18

The right pulmonary artery is longer than the left and passes horizontally across the mediastinum. It passes:
anteriorly and slightly inferiorly to the tracheal bifurcation and anteriorly to the right main bronchus; and
posteriorly to the ascending aorta, superior vena cava, and upper right pulmonary vein

Question 19

How does the left pulmonary artery lie in relation to other structures in the mediastinum?

Answer 19

The left pulmonary artery is shorter than the right and lies anterior to the descending aorta and posterior to the superior pulmonary vein (Fig. 3.45). It passes through the root and hilum and branches within the lung

Question 20

Describe the course of the pulmonary veins

Answer 20

On each side a superior pulmonary vein and an inferior pulmonary vein carry oxygenated blood from the lungs back to the heart. The veins begin at the hilum of the lung, pass through the root of the lung, and immediately drain into the left atrium.

Question 21

Which blood vessels supply the lungs with nutrients?

Answer 21

Bronchial arteries and veins
The bronchial arteries (Fig. 3.45) and veins constitute the “nutritive” vascular system of the pulmonary tissues

Question 22

Where do bronchial arteries originate from, where do they run?

Answer 22

• The bronchial arteries originate from the thoracic aorta or one of its branches:
• A single right bronchial artery normally arises from the third posterior intercostal artery (but occasionally, it originates from the upper left bronchial artery);
• Two left bronchial arteries arise directly from the anterior surface of the thoracic aorta:
• The superior left bronchial artery arises at vertebral level T5 and the inferior one inferior to the left bronchus.
• The bronchial arteries run on the posterior surfaces of the bronchi and branch many times in the lungs to supply pulmonary tissues.