Pleura & Pleural Cavities
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Transcript of Pleura & Pleural Cavities
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Developmental..
??
Where did it come from
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The pleural cavities
The thoracic cavity, the spaceenclosed by the thoracic walls,has three compartments
Two lateral compartments arethe pulmonary cavities that
contain the lungs and pleurae(lining membranes) & centralcompartment the
It is important to note that thelungs are not within the pleuralcavity.
The cavity is the spacebetween the visceral and
parietal layers of pleura. The lungs are surrounded by
the pleurae, a serousmembrane which folds backupon itself to form a two-layered, membrane structure.
The thin space between thetwo pleural layers is known asthe pleural space
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Pleural
A thin serous membraneinvaginated by the lung.
Intimately related to lung
Continuous over the rootof the lung with parietalpleura.
The Fist in glove model
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The pleura..
The visceral pleura(pulmonary pleura)
covers the lungs and
is adherent to all itssurfaces, including thesurfaces within thehorizontal and obliquefissures, it cannot bedissected from thelungs.
The parietal pleura
lines the pulmonarycavities, adhering to
the thoracic wall, themediastinum, and thediaphragm.
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The pleura
The parietal pleura consists Costal part (pleura)
covers the internal surfaces of thethoracic wall (sternum, ribs, costalcartilages, intercostal muscles andmembranes, and side of thoracicvertebrae)
separated from the wall byendothoracic fascia.
Mediastinal part (pleura) covers the lateral aspects of the
mediastinum (the centralcompartment of the thoraciccavity).
Diaphragmatic part (pleura) covers the superior or thoracic
surface of the diaphragm on eachside of the mediastinum.
Cervical pleura extends through the superior
thoracic aperture into the root ofthe neck
2-3 cm superior to the level of themedial third of the clavicle at thelevel of the neck of the 1st rib,
forming a cup-shaped dome overthe apex of the lung.
reinforced by a fibrous extension
of the endothoracic fascia, thesuprapleural membrane (Sibsonfascia) spanning between the 1strib and C7 vertebra.
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The pleura
Parietal pleura
Cervical
Costal
Diaphragmatic
Mediastinal
Visceral pleura
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The recesses
Costodiaphragmatic recesses
diaphragmatic pleura incontact with the lowermostpart of the costal pleura.
The potential space pleura
lined surround the upward convexity
of the diaphragm inside thethoracic wall
The costomediastinal recesses
the smaller pleural recessesposterior to the sternum w
costal pleura in contact withthe mediastinal pleura.
the left recess is potentiallylarger (less occupied) becauseof the cardiac notch in the leftlung.
The inferior borders of thelungs move farther into the
pleural recesses during deepinspiration and retreat fromthem during expiration.
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Fist invaginatingmodel -
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Pulmonary ligament.
Inferior to the root ofthe lung, this continuity
between parietal andvisceral pleura formsthe pulmonaryligament extendingbetween the lung and
the mediastinum.
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Pleural reflection
The cervical pleurae and apices
through the superiorthoracic aperture into theroot of the neck & posteriorto the clavicles.
The anterior borders of the lungs
anterior line of reflection ofthe parietal pleura betweenthe 2nd and 4th costalcartilages.
left pleural reflection
laterally & inferiorly at thecardiac notch to reach 6thcostal cartilage.
The anterior border of theleft lung
deeply indented by itscardiac notch.
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reflections
On the right pleural
reflection continuesinferiorly from the 4th to the6th costal cartilage,
paralleled anterior borderof the right lung.
Both pleural reflectionspass laterally and reach
the midclavicular line at 8thcostal cartilage,
10th rib at the midaxillaryline,
12th rib at the scapularline, to T12 vertebra.
Parietal pleura extendsapproximately two ribsinferior to the lung.
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Vasculature..
The veins fromthe parietal pleura
join the systemicveins in adjacentparts of thethoracic wall.
The veins fromthe visceral pleuradrain into thepulmonary veins.
Lymphatics-
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Vasculature..Lympahtics
The superficial(subpleural) lymphaticplexus drains lymph fromthe visceral pleura.
Lymph from the parietalpleura drains into thelymph nodes of thethoracic wall
(intercostal, parasternal,mediastinal, and phrenic).
A few lymphatic vesselsfrom the cervical pleuradrain into the axillarylymph nodes.
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Vasculature.. nerves
Visceralpleura- pleura nerve supply derive from the pulmonary plexuses located
anterior and (mainly) posterior to the roots of the lungs
These nerve networks contain parasympathetic fibers from the
vagus nerves (CN X) and sympathetic fibers from the
sympathetic trunks.
Parietal
Somatic intercostals nerves&phrenic
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Functional anatomy
The pleural cavity, with itsassociated pleurae,
aids optimal functioning of thelungs during respiration.
The pleurae are coated with
lubricating pleural fluid whichallows the pleurae to slideeffortlessly against each otherduring ventilation.
Surface tension of the pleuralfluid also leads to closeapposition of the lung surfaceswith the chest wall.
This physical relationship
allows for optimal inflation ofthe alveoli during respiration.
Movements of the chest wall,particularly during heavybreathing, are coupled tomovements of the lungs since
the closely opposed chest walltransmits pressures to thevisceral pleural surface and,hence, to the lung itself.
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Pleural fluid
Pleural fluid is a serous fluidproduced by the pleurae.
A normal 70 kg human hasapproximately 12-15 mL of pleuralfluid.
In normal pleurae, most fluid isproduced by the parietalcirculation (intercostal arteries) viabulk flow and reabsorbed by thelymphatic system.
pleural fluid is continuouslyproduced and reabsorbed.
The rate of reabsorption mayincrease up to 40x beforesignificant amounts of fluidaccumulate within the pleuralspace.
In humans, there is no anatomical
connection between the left andright pleural cavities, so in casesof pneumothorax, the otherhemithorax will still functionnormally.
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Functional anatomy..
Physiological Movements of membranes-
serous, smoothen
Injury to Pleurae The visceral pleura is insensitive
to pain innervation is autonomic (motorand visceral afferent).
The autonomic nerves reach thevisceral pleura in company withthe bronchial vessels. The visceralpleura receives no nerves ofgeneral sensation.
The parietal pleura is sensitive topain, particularly the costal pleura,because it is richly supplied bybranches of the somaticintercostal and phrenic nerves.
Irritation of the parietal pleuraproduces local pain andreferred pain to the areassharing innervation by thesame segments of the spinalcord.
Irritation of the costal andperipheral parts of thediaphragmatic pleura - localpain and referred pain alongthe intercostal nerves to thethoracic and abdominal walls.
Irritation of the mediastinaland central diaphragmaticareas of the parietal pleurapain - referred to the root ofthe neck and over theshoulder
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Functional, Injury ..
Cervical pleura Prone to stab injuries & surgeons knife
Niddle at 4th&5th ICS by pass the pleural to pericardium.
Pleural below 12th rib in the medial may be opened in the loin
(adrenal/renal surgery)
Pleural effusion
Empyema thoracis
Decortication
Tumours (mesotheliomas)