Human Anatomy Vol 1

The ceroical pleura extends into the neck, nearly 5 cm

above the first costal cartilage and 2.5 cm above the

medial one-third of the clavicle, and covers the apex of

the lung (seeFig. 12.10).It is covered by the suprapleural

membrane. Cervical pleura is related anteriorly to the

subclavian artery and the scalenus anterior; posteriorly

to the neck of the first rib and structures lying over it;

laterally to the scalenus medius; and medially to the

large vessels of the neck (see Fig. 12.10).

Diaphragmatic pleura lines the superior aspect of

diaphragm. It covers the base of the lung and gets

continuous with mediastinal pleura medially and costal

pleura laterally.

Surfoce Morking of Porielol PIeuro
The ceraical pleura is represented by a curved line
forming a dome over the medial one-third of the clavicle
with a height of about 2.5 cm above the clavicle
(Figs 15.5 and 21.1). Pleura lies in the root of neck on
both sides.
The anterior margin, the costomediastinal line of
pleural reflection is as follows: On the right side it
extends from the sternoclavicular joint downwards and
medially to the midpoint of the sternal angle. From here
it continues vertically downwards to the midpoint of
the xiphisternal joint crosses to right of xiphicostal
angle. On the left side, the line follows the same course
up to the level of the fourth costal cartilage. It then
arches outwards and descends along the sternal margin
up to the sixth costal cartilage.

THORACIC CAVITY AND PLEURAE

Theinferior margin, or the costodiaphragmatic line of

pleural reflection passes laterally from the lower limit

of its anterior margin, so that it crosses the eighth rib in

the midclavicular line, the tenth rib in the midaxillary

line, and the twelfth rib at the lateral border of the

sacrospinalis muscle. Further it passes horizontally a

little below the 12th rib to the lower border of the

twelfth thoracic vertebra, 2 cm lateral to the upper

border of the twelfth thoracic spine (Fig. 13.8a).

Thus the parietal pleurae descend below the costal

margin at three places, at the right xiphicostal angle,

and at the right and left costovertebral angles, below

the twelfth rib behind the upper poles of the kidneys.

The latter fact is of surgical importance in exposure of

the kidney. The pleura may be damaged at this site

(Figs 15.5 and 21.1).

The posterior margins of the pleura pass from a point

2 cm lateral to the twelfth thoracic spine to a point 2 cm

lateral to the seventh cervical spine. The costal pleura

becomes the mediastinal pleura along this line.

Pulmonory ligoment

The parietal pleura surrounding the root of the lung

extends downwards beyond the root as a fold called the

pulmonaryligament.Thefold contains a thinlayer of loose

areolar tissue with a few lymphatics. Actually it provides

a dead space into which the pulmonary veins can expand

during increased venous return as in exercise. The lung

roots can also descend into it with the descent of the

diaphragm (Fig. 15.5).

Visceral pleura

Right xiphicostal angle

Costomediastinal recess

Costodiaphragmatic recess

Cervical pleura

Costal pleura

Mediastinal pleura

Cardiac notch

Area of superficial

cardiac dullness

Lingula

Diaphragmatic pleura

Fig. 15.5: Surface projection of the parietal pleura (black); visceral pleura and lung (pink) oh the front of thorax