Human Anatomy Vol 1

THORACIC CAVIry AND PLEURAE

8. Bodies of the thoracic vertebrae behind oesophagus
   with posterior intercostal vessels and azygos vein
   lying over them.


9. Sympathetic trunk on the heads of the upper ribs
   and on the sides of the vertebral bodies below this,
   anterior to the posterior intercostal vessels and
   intercostal nerves.

Left side

1. Bulge of the heart (Fig. 15.2).


2. Root of lung posterosuperior to it.


3. Descending aorta between (1) and (2) in front and
   vertebral column behind.


4. Arch of aorta over the root of the lung.


5. Left common carotid and left subclavian arteries
   passing superiorly from the arch of aorta.


6. Phrenic and vagus nerves descending between
   these vessels and the lateral sudace of the aortic
   arch.


7. Sympathetic trunk same as on right side.
   ldentify longitudinally running sympathetic trunk on
   the posterior part of thoracic cavity. Find delicate greater
   and lesser splanchnic nerves arising from the trunk on
   the medial side. Look carefully for grey and white rami
   communicans between the intercostal nerve and the
   ganglia on the sympathetic trunk (see Fig. 14.3).
   Trace the intercostal vessels above the intercostal
   nerye. The order being vein, artery and nerve (VAN).
   On the right side, identify and follow one of the divisions
   of trachea to the lung root and the superior and inferior
   venae cavae till the pericardium.
   On the left side of thoracic cavity, dissect the arch of
   aorta. ldentify the superior ceruical cardiac branch of
   the left sympathetic trunk and the inferior cervical
   cardiac branch of the left vagus on the arch of the aorta
   between the vagus nerve posteriorly and phrenic nerve
   anteriorly.
   The cavity of the thorax contains the right and left
   pleural cavities which are completely invaginated and
   occupied by the lungs. The right and left pleural cavities
   are separated by a thick median partition called the
   mediastinum. The heart lies in the mediastinum.

Feolures

Like the peritoneum, the pleura is a serous membrane
which is lined by mesothelium (flattened epithelium).
There are two pleural sacs, one on either side of the
mediastinum. Each pleural sac is invaginated from its
medial side by the lung, so that it has an outer layer,
the parietal pleura, and an inner layer, the aiscernl or
pulmonary pleura. The two layers are continuous with

Fig. 15.1: Mediastinum as seen from the right side

Left common -

carotid adery

Oesophagus

Vagus nerve

Superior

vena cava

Phrenic nerve

Root of right

lung

Pericardium

Diaphragm

Oesophagus

Left

strbclavian

artery

Descending

aorta

Root of

left lung

Sympathetic

trunk

Oesophagus

Left vagus nerue

Arch of aorta

Left phrenic

nerve

Pericardium

Fig. 15.2: Mediastinum as seen from the left side

each other around the hilum of the lung, and enclose

between them a potential space, the pleural cavity.

Table 15.1 shows comparison between visceral

pleura and parietal pleura.

Pulmonory/Viscerol PIeuro

The serous layer of pulmonary pleura covers the

surfaces and fissures of the lung, except at the hilum

and along the attachment of the pulmonary ligament

where it is continuous with the parietal pleura. It is

firmly adherent to the lung and cannot be separateel

from it.

Surfoce Morking of lhe Viscerol Pleuro

The apex of the visceral pleura coincides with the

cervical pleura, and is represented by a line convex