Human Anatomy Vol 1

THORAX

Thoraeoepigastrre vein

Superficial epigastric

draining into great

saphenous vein

Y

Fig. 14.6: Obstruction to superior vena cava

2 The third to eleventh arteries arise from the
desceneling thoracic aorta (Fig. 14.8). The right-sided
arteries are longer than those of the left side as aorta
is to the left of median plane.

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In front of the aertebrae: The right posterior intercostal
arteries are longer than the left, and pass behind the
oesophagus, the thoracic duct, the azygos vein and the
sympathetie chain (Fig. 1a.9).
The left posterior intercostal arteries pass behind the
hemiazygos vein and the sympathetic chain.

Dorsal hranch

lnternal thoraeic artery

Fig. 14.72 Scheme showing the intercostal

and two anterior intercostal arteries

ln the intercostal spnce: The artery is accompanied by

the intercostal vein and nerve, the relationship from

above downwards being vein-artery-nerve (VAN).

The neurovascular bundle runs forwards in the costal

groove, first between the pleura and the internal

intercostal membrane and then between the internal

intercostal and intercostalis intimi muscles (Fig. 1,a.4.

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Each posterior intercostal artery ends at the level of the

costochondral junction by anastomosing with the uPPer

anterior intercostal artery of the space (Fig. 14.7).

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L A dorsal branch supplies the muscles and skin of

the back, and gives off a spinal branch to the spinal

cord and vertebrae (F\9. La.n.

2 A collateral branch arises near the angle of the rib,

descends to the upper border of the lower rib, and

ends by anastomosing with the lower anterior

intercostal artery of the space.

3 Muscular arteries are given off to the intercostal

muscles, the pectoral muscles and the serratus

anterior.

4 A lateral cutaneous branch accompanies the nerve

of the same name.

5 Mammary branches arise from the second, third and

fourth arteries and supply the mammary gland.

6 The right bronchial artery arises from the right third

posterior intercostal artery.

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There are nine intercostal spaces anteriorly as only ten

ribs reach front of body. There are two anterior

intercostal arteries in each space. In the upper six spaces,

they arise from the intemal thoracic artery. In seventh

Posterior intercostal artery

Collateral branch

Thoracic aorta Lateral cutaneous branch

Anterior intercostal arteries

arteries. Each intercostal space contains one posterior intercostal, its collateral branch