Transcript 19-Pleura & Lungs

Dr. Vohra
Pleura is a Double layered membrane that invests
both lungs, lies on either side of the mediastinum
within the chest cavity
Consists of:
Parietal layer
Lines the thoracic wall, covers the thoracic surface
of diaphragm & lateral aspect of mediastinum &
extends into root of neck
Visceral layer
Completely covers the outer surfaces of the lungs &
extends into the depth of the interlobar fissures
Pleural Cuff
Two layers continuous
with one another at the
hilum (structure leaving
& entering the lungs) of
the lungs
Pulmonary Ligament
To allow the movement
of pulmonary vessels &
bronchi during
respiration the pleural
cuff hangs down as a
loose fold
Pleural cavity/space
Is a slitlike space
between parietal &
visceral layers of pleura
Pleural fluid
To allow the movement
of pulmonary vessels &
bronchi during
respiration the pleural
cuff hangs down as a
loose fold
Is divided into:
1. Costal pleura
Lines the inner surfaces
of the ribs, costal
cartilages, intercostal
spaces, sides of the
vertebral bodies & back
of sternum
2. Diaphragmatic pleura
Covers the thoracic
surface of the diaphragm
3. Mediastinal pleura
Covers & forms the
lateral boundary of the
mediastinum
4. Cervical pleura
Also called as pleural
cupula/dome
Extends up into the
neck, lining the
undersurface of the
suprapleural membrane.
It reaches a level about 1
to 1 ½ inches above the
medial 3rd of clavicle
Each lung has a hilum on
its medial aspect. The
hilum of the lung is the
point of entry for the root
of the lung, which
includes the bronchi, the
pulmonary arteries, and
the pulmonary veins. A
pleural sleeve is created
around these structures,
where the pleura reflects,
changing from visceral
to parietal
Inferior to the hilum on each lung is the pulmonary
ligament, a continuation of that pleural reflection.
Costodiaphragmatic recesses
In quite respiration the costal & diaphragmatic pleurae
are in opposition to each other below the lower border
Of the lung. In deep respiration the margins of the base
of the lung descend, & both pleurae separate. This
lower area is called as Costodiaphragmatic recesses
Costomediastinal recesses
Situated along the anterior margin of the
pleura. A slitlike space b/w the costal &
mediastinal parietal pleura that are
separated by a capillary layer of pleural
fluid
Nerve supply
Parietal Pleura
Visceral Pleura
is sensitive PTTP
Costal pleura
Intercostal nerves
Mediastinal pleura
Phrenic
Diaphragmatic pleura
Domes by phrenic &
around the
periphery by the lower 6
intercostal nerves
The visceral pleura
receives an autonomic
supply from the
pulmonary plexus it is
sensitive to stretch but
insensitive to PTTP
Soft, spongy & elastic structure in thoracic cavity. If the thoracic
cavity were opened the lungs would immediately shrink to 1/3rd or
less in volume
In child it is pink in but becomes darker with the age because of the
inhalation of dust particles
Lie on each side of the mediastinum
Each lung is conical covered with visceral pleura & suspended free
in its own pleural cavity
External Features
Each lung has a blunt apex
Concave base sits on diaphragm
Surfaces
Costal surface correspond to the chest
Mediastinal surface
In the middle is a hilum (a depression) in which the bronchi,
vessels & nerves that forms the root enter & leave the lung
Borders
Anterior border of left lung is thin & overlaps the heart, it shows
cardiac notch
Posterior border is thick rounded & lies beside the vertebral
column
Lobes & Fissures
Right Lung
Is slightly larger than
the left & is divide by
the oblique &
horizontal fissure into 3
lobes the upper, middle
& lower lobes
Left lung
Divided by
similar oblique
fissure into 2
upper & lower
lobes
Cardiac notch
Blood supply
The bronchi, CT of the lung & visceral
pleura is supplied by bronchial arteries
branches of thoracic aorta
The bronchial vein drain into the
azygos & hemiazygos veins
Two pulmonary veins leave each lung
root to empty into the left atrium
Nerve supply
Pulmonary plexus composed of
autonomic nerve fibers of sympathetic
& parasympathetic (Vagus) both
Lymph Drainage
Two sets are present
Superficial
Lymph vessel re
not present in
alveolar walls
Drains the surface of the lungs
Deep
Drains bronchial tree, pulmonary
vessels & CT. Lymph drain into
bronchomediastinal trunk & finally to
thoracic duct, right lymphatic duct or
brachiocephalic veins