Human Anatomy Vol 1

THORAX

Remains of thymus

Manubrium sterni

Sternohyoid and sternothyroid muscles

Left common carolid artery

Left internal thoracic artery

Left brachiocephalic vein

Left vagus nerve

Left phrenic nerve

Subclavian artery

Thoracic duct

Left recurrent laryngeal nerve

Left lung

Left pleura

lnferior thyroid veins

Trachea

Oesophagus and

brach iocephalic artery

Right internal thoracic artery

Right brachiocephalic vein

Right phrenic nerve

Right vagus nerve

Right lung

Longus colli

Right pleura

First posterior intercostal vein

Posterior i ntercostal artery

First thoracic nerve

Sympathetic trunk

Ftg. 12.12: Structures passing through the inlet of the thorax

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1 Right and left internal thoracic arteries.
2 Right and left supedor intercostal arteries.
3 Right and left first posterior intercostal veins.
4 Inferior thyroid veins.

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1 Right and left phrenic nerves.

(^2) Right and left vagus nerves.
3 Right and left sympathetic trunks.
4 Right and left first thoracic nerves as they ascend
across the first rib to join the brachial plexus.
Museles
Stemohyoid, sternothyroid and longus colli.
c Thoracic inlet syndrome: Two structures arch over
the first rib-the subclavian artery and first
thoracic nerve. These structures may be pulled or
pressed by a cervical rib or by variations in the
insertion of the scalenus anterior. The symptoms
may, therefore, be vascular, neural, or both.
A cervical rib is a rib attached to vertebra C7. It
occurs in about 05% of subjects (Fig. 12.13). Such
a rib may exert traction on the lower trunk of the
brachial plexus which arches over a cervical rib.
Such a person complains of paraesthesia or
abnormal sensations along the ulnar border of the
forearm, and wasting of the small muscles of the
hand supplied by segment T1 (Fig. 12.14).
Vascular changes may also occur.
In coarctation or narrowing of the aorta, the
posterior intercostal arteries get enlarged greatly
to provide a collateral circulation. Pressure of the
enlarged arteries produces characteristic notching
on the ribs (Fig. 12.1,5) especially in their posterior
parts.
Fig. 12.13: Cervical rib on both sides
The inferior aperture is the broad end of the thorax
which surrounds the upper part of the abdominal
cavity, but is separated from it by the diaphragm
(Greek across fence).