Anatomy of the Pleura
Dr. U Offor
Pleura
• Has two layers:
– Parietal layer, which lines
the thoracic walls.
– Visceral layer, which
covers the surfaces of the
lung.
Pleura cuff
• The two layers
continue with
each other
around the root
of the lung,
where it forms
a loose cuff
hanging down
called the
pulmonary
ligament.
Parietal Layer
It lines the thoracic wall
Extends into the root of the neck to line the
under surface of the supra-pleural membrane
at the thoracic inlet
Parietal pleura
According to intrathoracic
surface it lines :-• Cervical pleura
• Costal pleura
• Diaphragmatic
pleura
• Mediastinal pleura
Divisions of parietal pleura
• 1-Cervical pleura:
It is part of parietal
pleura which
protrudes up into the
root of the neck.
• 2-Costal pleura:
It lines inner surface
of ribs, costal
cartilages, intercostal
muscles and back of
sternum.
• 3-Diaphragmatic
pleura:
It covers upper surface
of diaphragm.
• 4-Mediastinal pleura:
It covers mediastinal
surface of the lung.
Visceral Pleura
 firmly covers outer surfaces
of lung and extends into its
fissures.
 The 2- layers (mediastinal
parietal pleura & visceral
pleura) are continuous with
each other to form a tubular
sheath (pleural cuff) that
surrounding root of lung
(vessels, nerves & bronchi) in
the hilum of lung.
 On the lower surface of root
of lung, Pleural cuff hangs
down as a fold called
pulmonary ligament.
Pleural Cavity
 The parietal and visceral layers are separated
from one another by a slitlike space called
pleural cavity
 Pleural cavity contains thin film of tissue fluid
called pleural fluid
 Fluid permits the two layers to move on each
other with the minimum of friction
Recesses of pleura
– Costomediastinal recesses
– Costodiaphragmatic recesses
Recesses of pleura
 Costodiaphragmatic
recess :
lies between Costal &
diaphragmatic parietal
pleura.
 Costomediastinal
recess :
lies between costal &
mediastinal parietal
pleura.
Pleural Effusion
• It is abnormal
accumulation of pleural
fluid about 300 ml, in the
Costodiaphragmatic
recess , (normally 5-10 ml
of clear fluid)
• Auscultation would reveal
only faint & decreased
breath sounds over
compressed or collapsed
lung.
Pleurisy
• Inflammation of the pleura surrounding the
lungs
Applied anatomy : Aspiration of any fluid from the
pleural cavity is called parencentesis thoracis. It is
usually done in the 6th intercostal space in the
midaxillary line. The needle is passed through the lower
part of the space to avoid injury to the neurovascular
bundle.
Blood supply
• Arterial supply :
– Parietal pleura :
• Costal pleura : small branches of intercostal arteries
• Mediastinal pleura : supplied by pericardio phrenic artery
• Diaphragmatic pleura : supplied by superior phrenic and
musculophrenic artery.
– Visceral pleura :
• Bronchial artery : supplies visceral pleura facing the
mediastinum, pleura covering the interlobular surface and
part of the diaphragmatic surface.
• Pulmonary artery : supplies remaining portion.
• Venous drainage :
– Parietal pleura
• Through the intercostal veins which empty into inferior
venacava or brachio-cephalic trunk.
– Visceral pleura
• Through pulmonary veins.
Nerve supply
• Parietal pleura :
 Costal pleura : innervated by segmental intercostal
nerves.
 Peripheral part of diaphragmatic pleura :
innervated by lower 6 intercostal nerves.
 Central portion of diaphragmatic pleura and
mediastinal pleura :
 innervated by phrenic nerve.
• Visceral pleura :
– Innervated by autonomic nerves from the spinal
segments T4 and T5.