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LO: Applied Anatomy of the Thoracic Wall
Understand the concepts and associated principles, functional and clinical applications of;
4. The distribution of referred pain through the phrenic nerve
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Each phrenic nerve (from C3-C5) is the sole motor nerve motor nerve to the ipsilateral half of the
diaphragm. It also carries sensory fibres to the central part of that half, including the pleura
superiorly and the peritoneum inferiorly. The diaphragm also has sensory nerves from the
inferior intercostals muscles
Section of the phrenic nerve will lead to complete paralysis and eventually atrophy of the
muscular part of the corresponding half of the diaphragm
Pain resulting from irritation of the diaphragmatic pleura or the diaphragmatic peritoneum is
referred to the shoulder region (C4)
(Irritation of the peripheral regions of the diaphragm, innervated by the intercostals nerves, will
be referred more localised to the skin over the costal margins)
5.
The unique pattern of distribution of pain and rash in “shingles”
(reactivation of herpes zoster virus), affecting a thoracic spinal
nerve
Herpes zoster is primarily a viral disease of spinal ganglia, usually a
reactivation of the varicella-zoster virus. After invading a ganglion, the
virus produces a sharp burning pain in the dermatome supplied by the
involved nerve, the affected area becomes red and vesicular eruptions
occur.
6. The nerve supply of the pleurae (contrasting the innervations of parietal with that of the
visceral pleura)
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The nerves of the visceral pleura (and the lungs) are derived from the pulmonary plexuses
anterior and (mainly) posterior to the roots of the lungs
These networks contain the parasympathetic fibres from the vagus nerve and sympathetic fibres
from the sympathetic trunks
The nerves of the parietal pleura derive from the intercostals and the phrenic nerves
The costal pleura and the peripheral part of the diaphragmatic pleura are supplied by the
intercostals nerves and mediate sensations of touch and pain
The central part of the parietal pleura and the mediastinal pleura are supplied by the phrenic
nerves
The visceral pleura is insensitive to pain because it receives no nerves of general sensation
The parietal pleura (particularly the costal part) is extremely sensitive to pain – irritation may
produce local pain or referred pain projected to the dermatomes supplied by the same spinal
ganglia and segments of the spinal cord
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Irritation to the costal and peripheral parts of the diaphragmatic pleura result in local pain and
pain referred to the dermatomes of the thoracic and abdominal walls
Irritation of the mediastinal and central diaphragm of the parietal pleura results in referred pain
to the root of the neck and over the shoulder (C3 – C5)
7. An acceptable site (in terms of avoiding damage to structures) for the procedure of
intercostals drainage of; (i) pleural effusion (ii) pneumothorax. List the layers, (structures,
membranes, spaces) pierced
Appropriate sites for intercostal catheterization (which would be appropriate both in the treatment
of a pneumothorax, pleural effusion and a haemothorax);
 5th ICS just anterior to mid-axillary line
 2nd ICS mid-clavicular line
Layers pierced during the procedure;
 skin, superficial fascia
 serratus anterior (lateral approach) or pectoralis major/minor (anterior approach)
 external, internal, innermost intercostals muscles
 parietal pleura
 pleural cavity