Human Anatomy Vol 1

THOHAX

To the right:

L Right lung and pleura.

2 Greater splanchnic nerve.

To the left:

L Thoracic duct and aolta in lower part.

2 Oesophagus, tlachea and vagus in the upper part.

Iributories

(^1) Right superior intercostal vein forrned by union of
the second, third and fourth posterior intercostal
veins.
2 Fifth to eleventh right postelior intercostal veins
(Fig. 1a.10).
3 Hemiazygos vein at the level of lower border of
eighth thoracic vertebra.
(^4) Accessory hemiazygos vein at the level of upper
bordel of eighth thoracic vertebra.
5 Right bronchial vein, near the terrninal end of the
azygos vein.
5 Several oesophageal, mediastinal, pericardial veins.
HEMIAZYGOS VEIN
Hemiazygos vein is also called the inferior hemiazygos
aein. lt is the mirror image of the lower part of the
azygos vein. The hemiazygos is formed by the union of
the left lumbar azygos,left ascending lumbar, and left
subcostai veins.
Course
Herniazygos vein pierces the left crus of the diaphragm,
ascends on the left side of the vertebra overlapped by
the aorta. At the level of eighth thoracic vertebra, it turns
to the right, passes behind the oesophagus and the
thoracic duct, and joins the azygos vein (Fig. 14.10).
Tribulories
Ninth to eleventh left posterior intercostal veins and
oesophageal veins"
ACCESSORY HEMIAZYGOS VEIN
Accessory hemiazygos vein is also called the superior
hemiazygos aein.It is the mirror image of the upper part
of the azygos vein.
Coulse
Accessory hemiazygos vein begins at the medial end
of the fourth or fifth intercostal space, and descends
on the left side of the vertebral column. At the level of
eighth thoracic vertebra it turns to the right, passes
behind the aorta and the thoracic duct, and joins the
azl.gJos r.ein.
Iributories
L Fifth to eighth left posterior intercostal veins.
2 Sometirnes the left bronchial veins.
Feolules
The thoracic syrnpathetic trunk is a ganglionated chain
situated one on each side of the thoracic vertebral
column. Superiorly it is continuous with the cervical
part of the chain and inferiorly with the lun'rbar part
(Figs 14.13 and14.14).
Theoretically the chain bears 1,2 ganglia corres-
porlding to the 12 thoracic nerves. The first thoracic
ganglion is comrnonly fused with the inferior cervical
ganglion to form the cervicothoracic, or stellate ganglion.
The remaining thoracic ganglia generally lie at the levels
of the corresponding intervertebral discs and the
intelcostal nerves.
Coulse ond Relolions
The chain crosses the neck of the first rib, the heads of
the second to tenth ribs, and bodies of the eleventh and
twelfth thoracic vertebrae. The whole chain descends
in front of the posterior intercostal vessels and the
intercostal nerves, and passes deep to the rnedial
arcuate ligament tobecome continuous withthe lumbar
part of the sympathetic chain.
Bronches
Lateral Branches for lhe Lfmhs snd Body ll
Each ganglion is connected with its corresponding
spinal nerve by two rami, the white (preganglionic) and
grey (postganglionic) rami communicans. The white
rarnus is distal to the grey ramus. The grey rami
comrnunicans along with spinal nerves supply
structures in the skin and blood vessels of skeletal
muscles of the whole body (Fig. 14.74).
Medial Eranches for the Yiscero

1. Medial branches from the upper^5 ganglia
   are postganglionic and get distributed to the heart,
   the great vessels, the lungs and the oesophagus,
   through the following.
   a. Pulmonary branches to the pulmonary plexuses.
   b. Cardiac branches to the deep cardiac plexus.
   c. Aortic branches to thoracic aortic plexus.
   d. Oesophageal branches which join the oesophageal
   plexus.
   2 Medial branches from the lower^7 ganglia are
   preganglionic and form three splanchnic nerves.
   a. The greater splanchnic nerae is formed by^5 roots
   from ganglia 5 to 9. It descends obliquely on the
   vertebral bodies, pierces the crus of the