The diaphragm and Pleural cavity

Question 1

what does the diaphragm do

Answer 1

forms a portion between the abdomen and the thorax

The diaphragm is the main muscle of ventilation, descending into the abdomen on inspiration

Question 2

what is the inner part of the diaphragm called

Answer 2

central tendon

Question 3

describe the structure of the diaphragm

Answer 3

the outer part is muscular while the inner part, the central tendon, is fibrous and is firmly attached to the pericardium

Question 4

how is the diaphragm attached to the bony skeleton of the thorax

Answer 4

1. The sternal part is attached to the posterior aspect of the xiphoid process.
2. The costal part is attached to internal surfaces of the lower six ribs & costal cartilages.
3. The lumbar part attaches to the first 3 lumbar vertebrae posteriorly (around the aorta).

Question 5

how high does right dome of the diaphragm come

Answer 5

The right dome reaches as high as the upper border of the 5th rib

Question 6

how high does the left dome of the diaphragm come

Answer 6

he left dome reaches the lower border of the 5th rib

Question 7

what are the structures that pass through the diaphragm and where do they pass through it

Answer 7

1. The inferior vena cava. This is the main vein taking blood from the abdomen and lower limbs back to the heart. The inferior vena cava pierces the central tendon of the diaphragm at the level of the 8th thoracic vertebra (T8) to the right of the midline.
2. The oesophagus. The oesophagus passes through the diaphragm slightly to the left of the midline and level with the 10th thoracic vertebra (T10).
3. The aorta. The aorta passes through the diaphragm (or, strictly speaking, behind it) at the level of the 12th thoracic vertebra (T12).

Question 8

describe the phrenic nerve and what it innervates

Answer 8

• it is sensory to the mediastinal pleura and pericardium and some of the parietal pleura covering the diaphragm

Question 9

describe the different types of pleura

Answer 9

1. It extends above the first rib into the neck forming the cervical pleura.
2. The diaphragmatic pleura covers the superior surface of the diaphragm on each side of the heart.
3. The mediastinal pleura covers the lateral surface of the mediastinum (the central part of the thorax, between the lungs, which contains the heart, the great vessels, the oesophagus and other structures).
4. The costal pleura covers the thoracic wall

Question 10

what happens to costal and diaphragmatic pleura in respiration

Answer 10

In quiet respiration the costal and diaphragmatic pleurae are in opposition to each other, below the lower border of the lung

Question 11

what happen in deep inspiration to costal and diaphragmatic pleura

Answer 11

In deep inspiration, the diaphragm (and therefore the lung base) descends and the costal and diaphragmatic pleurae separate. This lower area of the pleural cavity into which the lung expands is called the COSTODIAPHRAGMATIC RECESS – this is also known as the costophrenic recess