Thorax Anatomy 2.5 Flashcards Preview

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Flashcards in Thorax Anatomy 2.5 Deck (55)
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1
Q

How is innervation of the muscles of the internal intercostal spaces and the skin overlying the intercostal spaces derived from?

A

The intercostal nerves

2
Q

How many intercostal nerves are there?

A

-There are 11 pairs of intercostal nerves plus one sub-costal nerve below the 12 ribs.

3
Q

What sort of nerves are intercostal nerves?

A

-They are mixed nerves, i.e, they have motor and sensory components.

4
Q

What are the cutaneous branches?

A
  • The cutaneous branches supply the skin overlying the intercostal spaces.
  • Lateral cutaneous branches: divide into anterior and posterior branches
  • Anterior cutaneous branch: divides into a medial and lateral branch.
5
Q

What does the motor component of the intercostal nerve serve?

A

-The motor component of the intercostal nerve serves to innervate and provide the intercostal muscles with motor innervation to enable contraction.

6
Q

What is the supply of the intercostal spaces?

A
  • The intercostal spaces also have an arterial supply from branches of the descending aorta and also from the internal thoracic arteries
  • Venous drainage is via the azygous vein or the internal thoracic veins.
7
Q

What do the neurovascular bundles run?

A

-The neurovascular bundles run in the superior aspect of the intercostal space.

8
Q

Where do you insert a chest drain?

A

-The anatomical relations of these vessels and nerves to the intercostal space means that they are vulnerable to traumatic injury or when inserting a chest drain to remove air or blood. -To minimize damage to the blood vessels, muscle, and breast tissue, a chest drain can be inserted into an area known as the safe area shown on this slide here as the shaded area. -The boundaries of this safe area are the anterior border of latissimus dorsi, the lateral border of the pectoralis major muscle, above a line that’s superior to the horizontal level of the nipple, and below the apex of the axilla. -The drain should be inserted on the superior surface of the rib to avoid potential damage to the neurovascular bundle which is running in the superior aspect of the intercostal space.

9
Q

How is the trachea held open?

A

-by C-shaped cartilaginous rings which are open posteriorly -the lowest cartilaginous ring has a hook. This is known as the carina as it resembles the keel of the ship.

10
Q

What happens at the lowest cartilaginous ring?

A

-At this vertebral level which is T4 T5 with a trachea extending from cervical C6, the trachea bifurcates into a principal left bronchus and a principal right bronchus.

11
Q

Which bronchus is larger

A

-The right main bronchus is wider and more vertical than the left -This is relevant as inhaled objects can often descend into the right main bronchus rather than the left main bronchus and end up in the right lung.

12
Q

What does the main branches divide into?

A

-lobar or secondary bronchi –These supply the lobes of the lungs, and they are formed within the substance of the lungs

13
Q

What do the lobar branch divide into?

A

-The lobar bronchi further divide into segmental or tertiary bronchi, which supply the bronchopulmonary segments.

14
Q

What do the segmental or tertiary branch supply?

A

-These supply the bronchopulmonary segments which are the smallest functionally independent regions of the lungs. -There are ten on each side as shown on the right of this slide

15
Q

How are the lungs separated from each other?

A

by the heart and other contents of the mediastinal

16
Q

What does each lung lie in?

A

-Each conical shaped lung lies freely its plural cavity apart from its attachment to the heart via pulmonary vessels and the trachea at the lung route. -The apex of the lung rises three to four centimeters superiorly to the level of the first costal cartilage. -The base of the lung rests on the convex surface of the diaphragm

17
Q

What are the three borders of the lungs?

A

anterior, posterior and inferior

18
Q

What are the surfaces of the lungs?

A

a costal surface, which is closest to the ribs, a medial surface, known as the mediastinal surface and an inferior surface, known as the diaphragmatic surface

19
Q

What does the diaphragm do?

A

-The diaphragm which sits inferiorly to the lungs separates the right lung from the right lobe of the liver and the left lung from the left lobe of the liver, and also the stomach and the spleen

20
Q

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

A

-there is a posterior part which is in contact with the thoracic vertebra -anterior part which is deeply concave and accommodates the heart

21
Q

Where is the cardiac impression larger ?

A

the cardiac impression is larger on the left side than the right because of the positioning of the heart

22
Q

What is above and behind the cardiac impression?

A

-Above and behind the cardiac impression is the hilum of the lung -the point at which vessels and airways and nerves leave and enter the mediastinum.

23
Q

What are the two lobes in the left lung?

A

superior and inferior

24
Q

What are the two lobes separated by?

A

oblique fissure

25
Q

Where does the superior lobe lie and what does it include?

A

-The superior lobe lies above the fissure and includes the apex of the lung and most of the anterior part of the lung

26
Q

Where is the inferior lobe?

A

below the oblique fissure and contains most of the posterior part of the lung

27
Q

What are the three lobes in the right lung? What are they separated by ?

A

-Superior -Middle -Inferior -Separated by two fissures

28
Q

What fissures does the right lung have?

A
  1. Oblique fissure: separates the inferior lobe from the other two lobes 2. Horizontal fissure: separates the superior from the middle lobe
29
Q

Which lung is larger?

A

The right

30
Q

What does the root of the lung do?

A

-Connects the mediastinal surface to the heart and trachea -It is formed by structures that enter or leave the hilum

31
Q

What are structures that enter of leave the hilum?

A
  1. principle or primary bronchi 2. the pulmonary artery taking deoxygenated blood from the right ventricle 3. two pulmonary veins, which are returning oxygenated blood to the left atrium 4. the bronchial arteries, which are transporting oxygenated blood from the descending aorta, and veins. 5. There are also autonomic nerves, lymph vessels, and nodes. -All of these are enveloped in pleural.
32
Q

What is the pleura?

A

-This is a thin layer of flattened cells that lines each of the pleural cavities and covers the outside surface of the lungs -It’s composed of two layers

33
Q

What are the two layers of the pleura?

A

-The layer that is closest to the lung surface is the visceral pleura -The layer that is closest to the inner surface of the chest wall is known as the parietal pleura -They are continuous with each other around the root of the lung (hilum)

34
Q

What happens in health?

A

-the pleural cavity is collapsed but there is the moist surfaces allow the lungs to glide as they expand during inspiration and collapse during expiration

35
Q

What can you see from an anterior dissection with pulmonary vessels and bronchi passing from mediastinum to the lungs?

A

-We can see here the pulmonary trunks cut edge would be continuous with the pulmonary trunk here anteriorly. -We would see that the aorta here is continuous with the aorta here. -We can see the superior vena cava entering the right atrium and we can see here the formation of the superior vena cava by the union of the left brachiocephalic vein and the right brachiocephalic vein. -Into the back of the superior vena cava, we can see the azygous vein, which is draining the posterior wall of the chest. -Coming into the back of the left atrium are the pulmonary veins which are bringing highly oxygenated blood back from the lungs to be transported via the systemic circulation to the entire body.

36
Q

What is breathing controlled by?

A

-by the nervous system and produced by contractions of skeletal muscles -It brings about inhalation and exhalation of air into and out of the lungs, to ventilate the gas exchange areas which are the alveolar sacs

37
Q

How can capacity of the thoracic cavity be increased?

A

-Capacity of the thoracic cavity can be increased by movements of the diaphragm and also by movements of the ribs

38
Q

What happens when the chest is expanded?

A

-When the chest is expanded by the actions of the diaphragm and movements of the sternum and the ribs, the pleural cavity is also expanded

39
Q

What happens with elastic lungs?

A

-The elastic lungs expand within the pleural cavity, and the resulting negative pressure causes air to be sucked into the trachea and bronchi, and down into the lungs. Quiet expiration is a passive activity not requiring muscle contraction. -It depends upon the elastic recoil in the tissue throughout the lungs and in the rib cage. -During deep or forced expiration, this is assisted by the muscles of the abdominal wall that squeeze the abdominal organs against the diaphragm and pull the lower ribs downwards.

40
Q

When happens during inspiration?

A

-When the diaphragm contracts following motor commands delivered via the phrenic nerve from the spinal cord segments, C3, 4, and 5, -The vertical dimension of the thoracic cavity is increased. In doing so, the diaphragm presses on the abdominal organs which initially descend because of the relaxation of the abdominal wall during inspiration.

41
Q

How is further descent stopped?

A

-By abdominal viscera -So more diaphragm contractions raises the costal margin upwards

42
Q

What reduced intrasplural pressure?

A

-Increased thoracic capacity produced by the diaphragm and rib movements in inspiration reduces intraplural pressure with the entry of air through respiratory passages and expansion of the lungs.

43
Q

What is at the margin of a diaphragm?

A

Skeletal muscle and a central sheet like tendon

44
Q

What is a safe area for inserting a chest tube?

A
45
Q

Summarise the lungs

A
46
Q

Descibe the mediastina surface of the lung

A
47
Q

Describe the left side of lung

A
48
Q

Descibe the right lung

A
49
Q

What is the hilum?

A
50
Q

What is the pleura?

A
51
Q

Descibe the mechanisms of breathing

A
52
Q

Describe the breathing

A
53
Q

Descirbe the diaphragm

A
54
Q

What is the throacic surface of the diaphragm like?

A
55
Q

Where are the ribs?

A