2. The pleural is a double layered serous membrane linning the
thorax and enveloping the lungs.
The pleural cavity on each side is almost completely filled by
a lung, leaving a the cavity as a potential space containing a
thin film of fluid (pleural fluid).
The pleura is in two layers, the visceral pleura and parietal
pleura.
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3. Parietal Pleural: lines the thoracic cavity on each side of the
mediastinum.
Visceral Pleural: covers the outer surface of the lung and is
continuous at the hilum with the parietal pleura.
Unlike the parietal pleura, the visceral pleura dips into the
lung fissures; therefore, in the fissures, the visceral pleura of
adjacent lobes lie in contact with each other
The pleural cavity on each side is almost completely filled by
a lung, leaving a the cavity as a potential space containing a
thin film of fluid (pleural fluid).
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5. Dare Samuel S. 5
Costal Pleura: covers the internal surfaces of the sternum,
costal cartilages, ribs, intercostal muscles and the sides of
thoracic vertebrae, separated from all these structures by a thin
layer of loose connective tissue called the endothoracic fascia.
Mediastinal Pleura: covers the mediastinum, it is continuous
anteriorly and posteriorly with the costal pleura. Superiorly it
is continuous with the cervical pleura and Inferiorly is
continues with the diaphragmatic pleura
Diaphragmatic Pleura: covers the superior surface of the
diaphragm
6. Cervical Pleura: The is also called the cupola of the pleura. It
extends through the superior thoracic aperture into the root of
the neck.
Its summit is 2-4 cm superior to the medial 1/3rd of the
clavicle.
It does not extend superior to the neck of the first rib because
the first rib slopes inferiorly.
Extension of the lung and pleura into the root of the neck
make them liable to be injured in wounds of the neck
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8. Think of even numbers.
The cervical pleura extends
into the neck 2-4cm above
the medial third of the
clavicle
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9. From this point, the pleura
passes behind the
sternoclavicular joint
reaching the midline at the
level of the 2nd costal
cartilage.
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10. From here, the two pleural
cavities are in contact as far
as the 4th cartilage, here the
right pleura continues
vertically down to the level
of the 6th costal cartilage
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11. Here the right pleura
continues vertically down
to the level of the 6th costal
cartilage
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12. The left pleura arches
laterally at the level of the
4th costal cartilage and
descends lateral to the
border of the sternum down
to the level of the 6th costal
cartilage
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13. At the level of the 6th costal
cartilage the pleura on both
sides pass around the chest
wall crossing the 8th rib at
the mid-clavicular line
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14. The pleura on both sides
pass around the chest wall
crossing the 10th rib at the
mid-axillary line
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15. The pleura on both sides
pass around the chest wall
crossing the 12th rib at the
back
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16. is an ill-chosen name (a misnomer), it
has nothing to do with the lung since it
is pleura;
the pulmonary ligament is not a
ligament in the correct sense of the
meaning, it is a double fold of pleura
that hangs down below the lung root as
an empty fold
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17. It provides a dead space into which the lung root descends
with descent of the diaphragm.
Pulmonary veins (contained in the lung root) can expand
during periods of increased venous return from the lungs as in
exercise.
The two pulmonary veins at each root lie at the lower part of
the root just above the pulmonary ligament
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18. The previously-mentioned lines are
called lines of pleural reflection.
The sternal pleural reflection is
where the costal pleura is
continuous with the mediastinal
pleura posterior to the sternum
The costal pleural reflection is
where the costal pleura is
continuous with the diaphragmatic
pleura near the costal margin.
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19. The vertebral reflection lies
posteriorly along the lateral side
of the bodies of thoracic
vertebrae.
The mediastino-diaphragmatic
reflection connects the inferior
ends of the sternal and vertebral
reflections
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20. The lung markings correspond
to those of the pleura above but
are two ribs higher in the lower
part of the thorax.
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21. Thus the lung reaches the
level of the 6th costal cartilage
or rib in the mid-clavicular
line, 8th rib in the mid-axillary
line
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22. The lung reaches the level of
the 10th rib posteriorly
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23. During full inspiration, the
lung expands and fill the
pleural cavity; but during quiet
inspiration there are three sites
where the lung does not fully
occupy the pleural cavities.
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24. At these sites the two layers of
parietal pleura are in contact with
each other at their inner surfaces.
The sites where parietal pleura
comes into contact with parietal
pleura are called pleural recesses
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25. The pleural recesses are only
occupied by lung tissue
during full inspiration, they
are the right and left costo-
diaphragmatic recesses and
the costo-mediastinal recess
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26. Is located at the inferior
margin of the pleura
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28. Excess fluid in the
pleural cavity will
cause an opacity which
obliterates the angle
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29. Lies along the anterior margin
of the pleura where the costal
angle and mediastinal parts of
the left pleura come into
contact at the cardiac notch in
the anterior border of the left
lung where it overlies the
heart.
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30. Lies at the anterior ends of
the 4th and 5th intercostal
spaces and during full
inspiration it becomes
occupied by the lingula of
the left lung
4
5
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31. The pleura descends
inferior to the costal
margin in three regions
1- the right infrasternal
angle
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32. 2 & 3: The right and
left costovertebral
angles.
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33. This is especially important
for the costo-vertebral angles
Which are located behind the
upper pole of the kidney and
are liable to be opened while
incising for nephrectomy
(removal of the kidney)
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34. The visceral pleura
should be regarded as
part of the lung, the
parietal pleura as part
of the chest wall.
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35. The nerve supply of the
visceral pleura as in the
lung is autonomic through
nerves that accompany the
bronchial arteries, these are
vasomotor.
The visceral pleura is thus
insensitive to ordinary
stimuli as pain and touch.
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36. The parietal pleura as
part of the chest wall is
supplied by somatic
nerves namely intercostal
and phrenic nerves.
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37. The collateral branches
of intercostal nerves
segmentally supply the
costal pleura and the
peripheral part of the
diaphragmatic pleura
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38. The central part of the
diaphragmatic pleura and
the mediastinal pleura are
supplied by the phrenic
nerves.
The parietal pleura is thus
sensitive to pain.
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39. Irritation of the costal and peripheral part of the diaphragmatic
pleura by disease causes local pain and referred pain i.e. pain
referred or seems to be arising from regions supplied by the
same intercostal nerves that supply the pleura.
Thus pain is referred to the chest and abdominal walls that are
both supplied by intercostal nerves
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40. Irritation of the mediastinal or
central part of the
diaphragmatic pleura supplied
by the phrenic nerve is
referred to the tip of the
shoulder where the
dermatome there is that of C4
since the root value of the
phrenic nerve is C3, 4, and 5
mainly C4
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41. Irritation of the parietal
peritoneum below the
diaphragm (which is also
supplied by the phrenic
nerve) is also referred to
the tip of the shoulder
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42. The visceral pleura
derives its arterial supply
froth bronchial arteries
that supply lung tissue
with oxygenated blood
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43. The bronchial arteries
are branches of the
thoracic aorta.
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44. The blood supply of the
parietal pleura is derived
from that supplying the
chest wall namely internal
thoracic, intercostal, and
musculophrenic arteries
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45. The pleural cavity is a
potential space containing
a thin film of pleural fluid
The pressure inside the
cavity is slightly below
atmospheric
The pressure inside the
lung is more or less
atmospheric.
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46. This is accumulation of air in
the pleural cavity
If the chest wall is penetrated
following for example;
a stab wound or
the visceral pleura is punctured
usually as a result of rupture of
bullet on the surface of the lung,
Air enters the pleural cavity so
that its pressure becomes the
same as that inside the lung;
since the lungs are more elastic,
the lungs tend to collapse
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47. Sometimes air enters
the pleural cavity
during inspiration
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48. But air cannot leave during
expiration causing an
increased accumulation of
air (positive pressure
pneumothorax).
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49. This is dangerous since air
accumulation will not only
compress the ipsilateral lung but
it will push the mediastinum to
the other side compressing the
opposite lung and killing the
patient
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50. 50
The presence of excess fluid
in the pleural cavity.
The fluid tends to gravitate
towards the costomediastinal
recesses, thus, it obliterates
the costophrenic angle.
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51. 51
Accumulation of more fluid,
like in pneumothorax, tends
to collapse the lung and
displace the mediastinum to
the other side
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