III.A.1 Thorax: Mediastinum: Page 1 of 6

OBJECTIVES:

1.1.1 Identify the boundaries and divisions of the mediastinum and point to all structures in each part.

1.1.2 Demonstrate the projection of the thoracic diaphragm on the thoracic wall.

1.1.3 Follow the course and show the anatomical relationships of the phrenic nerve from its origin in the neck to the diaphragm.

1.1.4 Trace the course of the vagus nerve and its branches through the mediastinum.

1.1.5 Identify the recurrent laryngeal, cardiac, pulmonary, and esophageal branches of the vagus nerve going to the target organs.

1.1.6 Identify the sympathetic trunk and the greater splanchnic nerve.

1.1.7 Trace the flow of blood in the azygos system and indicate any collateral connections to other parts of the systemic venous system.

1.1.8 Trace the flow of lymph through the thoracic duct from its origin to its termination and indicate the source of afferent lymphatics to the duct.

READINGS:

Moore's COA: Pages 348-403, 533-537, 997, 1005-06. See the blue boxes on pages 352-355, 372-381, 396-403 for clinical correlations. See the yellow boxes on pages 355, 381-82, 404 for "The Bottom Line."

	Begin with the thoracic cage.	Tap on image to enlarge
	Add the thoracic duct.
Notice that the thoracic duct begins in the abdomen with the cisterna chyli (chyle is the name for the contents that flows through the lympahatic system). This duct empties into the left brachiocephalic vein.

	Add the azygous vein.
Zygous means two, therefore an Azygous vein means "not" two. You can see the remnents of the two veins with the hemizygous vein. The azygous vein empties into the superior vena cava.
	Add the diaphragm.
Notice that both the hemizygous veins and the thoracic duct leave the abdomen near the crus of the diaphragm that allows the aorta to pass from the thorax to the trunk. Rotate the cadaver to get a sense of this relationship.