Human Anatomy Vol 1

Brachiocephalic trunk

Ascending aorta

lntercostal arteries

Subcostal artery

Left subclavian artery

Left common carotid artery

Arch of aorta

Bronchial artery

Oesophageal artery

Pericardial artery

Diaphragm

WALL OF]-HORAX

On lefl side

they drain into

Accessory hemiazygos

vetn

Hemiazygos vein

Fig. 14"8: Branches of descending thoracic aorta

Thoracic duct

Azygos vein

Posterior

intercostal

artery

Vertebral body

Sympathetic

trunk

Hemiazygos

vein

FIg. 14.9: The origin of the right and left posterior intercostal
arteries from the aorta. Note that the arteries are longer on the
right side

to ninth spaces/ the arteries are branches of musculo-
phrenic artery. The two anterior intercostal arteries end
at the costochondial junction by anastomosing with the
respective posterior intercostal arteries and with the
collateral branches of the posterior intercostal arteries.

lntarcoslal Veins

There are tw o anterior intercostal aeins in each of the upper
nine spaces. They accompany the corresponding
arteries. In the upper three six spaces, the veins end in
the internal thoracic vein. In 4-6 spaces, the veins end in
vena comitantes accompanying internal thoracic artery.
In the succeeding spaces, they end in the vena comitantes
accompanying musculophrenic artery.
There is one posterior intercostal aein and one collateral
vein in each intercostal space. Each vein accompanies
the corresponding artery and lies superior to the artery,

The tributaries of these veins correspond to the branehes

of the arteries. They include veins fron=r the vertebral

canal, the vertebral venous plexus, and the muscles and

skin of the back. Vein accompanying the collateral

branch of the artery drains into the posterior intercostal

vein.

The mode of termination of the posterior intercostal

veins is different on the right and left sides as given in

Table1,4.2, and shown in Fig. 14."10.

The azygos and hemiazy9os veins are described

later.

Lymphotics of on lnlercoslolSpoce

Lymphatics from the anterior part of the sPaces pass to

the arrterior intercostal or internalmammary nodeswhich

lie along the internal thoracic artery. 'Iheir efferents unite

Table 14.2: Termination of posterior intercostal veins

1st Right brachiocephalic Left brachiocephalic

vein vein

2nd, 3rd, Join to form right Join to form left superior

4th superior intercostal intercostal vein which

vein which drains into drains into the left

the azygos vein braehioeephalie vein

Veins On right side

they drain into

Sth to 8th Azygos vein

9th to 11th Azygos vein

and

subcostal