Human Anatomy Vol 1

THORAX

Horizontal fissure

Middle lobe

Right xiphicostal angle

Costomediastinal recess

Costodiaphragmatic recess

Tlte louter border of each lung lies two ribs higher than
the parietal pleural reflection. It crosses the sixth rib in
the midclavicular line, the eighth rib in the midaxillary
line, the tenth rib at the lateral border of the erector
spinae, and ends 2 cm lateral to the tenth thoracic spine.
The posterior border coincides with the posterior
margin of the pleural reflection except that its lower
end lies at the level of the tenth thoracic spine.

The oblique fissure can be drawn by joining:
1 A point 2 cm lateral to the third thoracic spine.
2 Another point on the fifth rib in the midaxillary
line (Figs 21.2 and27.3).
3 A third point on the sixth costal cartilage 7.5 cm
from the median plane.
The horizontal fissure is represented by a line joining:
L A point on the anterior border of the right lung at
the level of the fourth costal cartilage.
2 A second point on the fifth rib in the midaxillary
line (Fig.21.2).
Between the visceral and parietal pleurae the recesses
are present. Costodiaphragmatic are present on both
sides and are about 4-5 cm deep. Costomediastinal is
prominent on left side, to left of sternum between 4th
and 6th costal cartilages.

Suffoce Morking of ihe Borders of the Heort

The upper border is marked by a straight line joining:

(^1) A point at the lower border of the second left costal
cartilage about 1.3 cm from the sternal margin.
Cervical pleura
Cardiac notch
Cardiac area
Oblique fissure
Lingula
(^2) A point at the upper border of the third right costal
cartilage 0.8 cm from the sternal margin (Fi9.21.5).
The lower border is marked by a straight line joining:
L A point at the lower border of the sixth right costal
cartilage 2 cm from the sternal margin.
2 A point at the apex of the heart in the left fifth
intercostal space 9 cm from the midsternal line.
The right border is marked by a line, slightly convex
to the right, joining the right ends of the upper and
Upper
border
Right
border
Left
border
Left
nipple
Lower
border
Fi$.21.4: Surface projection of the parietal pleura (black); visceral pleura and lung (pink) on the front of the thorax
Fig. 21.5: Surface projection of the borders of the heart