LAB: Superior & Posterior Mediastinum
Created by Cristobal Goa, '09
and Nicholas Cohen, '09
LEARNING OBJECTIVE:
SLIDE #1
INTRODUCTION AND TABLE OF RELATIONSHIPS
The Superior Mediastinum and Posterior Mediastinum are full of interesting and important relationships. While there is not very much terminology to master, the positions of structures relative to one another can be overwhelming if one does not approach them in a careful and systematic way. This module will attempt to guide the student through some of the important sets of relationships that are found in this region of the thorax.
SOME IMPORTANT RELATIONSHIPS
Level of the Sternal Angle/T4-T5 Intervertebral Disc |
Aortic Arch, Azygous Arch, Superior Vena Cava formed |
Trachea Bifurcates at T5 |
Pulmonary Trunk bifurcates anterior to the bifurcation of the trachea |
RIGHT Brachiocephalic Vein does not cross midline and is much shorter than the Left Brachiocephalic Vein |
LEFT Brachiocephalic Vein crosses anterior to Left Subclavian Artery, Left Common Carotid Artery, and Brachiocephalic Trunk from left to right |
Azygos vein arches over the root of the RIGHT lung from posterior to anterior |
Aortic Arch passes posteriorly & towards the left over the root of the LEFT lung from anterior to posterior (also anterior & superior to the Right Pulmonary Artery) |
Right & Left Vagus Nerves descend posterior to the roots of the lungs on their respective sides |
Right and Left Phrenic Nerves descend anterior to the roots of the lungs on their respective sides |
Left Superior Intercostal Vein separates the Left Phrenic Nerve (anterior to the vein) from the Left Vagus Nerve (posterior to the vein), which run quite close together lateral to the Aortic Arch. |
|
RIGHT Vagus Nerve enters the thorax between the Right Brachiocephalic Vein & the Brachiocephalic Trunk |
LEFT Vagus Nerve enters the thorax with the Left Common Carotid Artery |
RIGHT Recurrent Laryngeal Nerve recurs around the Right Subclavian Artery in the neck |
LEFT Recurrent Laryngeal Nerve recurs around the Aortic Arch, postero-lateral to the Ligamentum Arteriosum |
The Esophagus begins POSTERIOR to the Trachea to the LEFT of the midline, is pushed to the RIGHT of the midline by the Aortic Arch, and then crosses Anterior to the Descending Aorta towards the LEFT in the lower posterior mediastinum to cross through the diaphragm to the LEFT of the midline, where it connects with the Stomach |
|
Both the Right & Left Brachiocephalic Veins are formed posterior to the Right & Left Sternoclavicular joints, respectively. |
|
The above table represents an attempt to pair some of the important relationships in the Superior and Posterior Mediastinums to make comparisons between the two sides of the thorax and hopefully make them easier to understand and remember.
