1.2.1 Mediastinum

Question 1

Describe the subdivisions of the medistinum.

Answer 1

Superior: sits above the sternal angle of louis

Inferior: subdivided into anterior, middle, and posterior

Middle: includes heart and pericardium

Question 2

In what region of the mediastinum is the thymus located?

Answer 2

Anterior part of the superior mediastinum

Question 3

From which arteries does the thymus recieve its arterial supply?

Answer 3

inferior thyroid and anterior intercostals

Question 4

Thymoma, tumors of the thymus, can grow and affect what structures in the surrounding area of the body?

Answer 4

SVC, trachea, and occasionally other mediastinal structures

Question 5

Which two veins come together, occurs bilaterally, to form the brachiocephalic vein?

Answer 5

Internal jugular vein and subclavian vein

Question 6

Decribe the branching of the SVC as it travels distally from the heart?

Answer 6

Bifurcates into the R/L brachiocephalic, branch of internal jugular, branch of external jugular, called the subclavian vein, called the axillary vein, called the brachial vein

Question 7

What are the 3 parts of the thoracic aorta?

Answer 7

Ascending - begins in pericardial sac and ascends behind sternal angle

Arch - lies behind manubrium in front of trachea

Descending - begins at sternal angle and descends just anterior to vertebral bodies

Question 8

Describe the spatial relationship of the SVC, Aorta, R/L pulmonary arteries, trachea, and esophagus.

Answer 8

Question 9

What are the first three branches off of the aorta?

Answer 9

Just remember your ABCS!

A - Arch of Aorta

B - Brachiocephalic

C - Left Common carotid

S - Subclavian

Question 10

Describe the spatial relationship b/t the trachea and esophagus.

Answer 10

Trachea just anterior to esophagus

Question 11

Where does the trachea typically branch into the primary/main bronchi (the carina of the trachea)?

Answer 11

The sternal angle or ~T4-T5

Question 12

If a foreign object is inhaled, which main bronchi is typically occluded? Why?

Answer 12

The right main bronchus b/c it has a larger diameter and runs slightly more vertical

Question 13

When the esophagus enters the superior mediastinum it is sandwiched b/t which two structures?

Answer 13

Trachea and vertebral column

Question 14

What is the 8-10-12 rule?

Answer 14

The 8-10-12 rule refers to the vertebral position in which the three tubes pass through the diaphragm.

IVC passes through at the level of T8

Esophagus passes through at the level of T10

Aorta passes through at the level of T12

Question 15

The phrenic nerve arises from which ventral rami?

Answer 15

C3, C4, C5

Question 16

The phrenic nerve runs external to the fibrous pericardium on its way to innervating what structure?

Answer 16

The diaphragm

Question 17

Identify the three structures.

Answer 17

Question 18

What are the three different locations that pain originating from the diaphragm can be felt?

Answer 18

T7-10 anteriorly,

T11-12 posteriorly

reffered to cervial levels C3-5 due to phrenic innervation

Question 19

What parasympathic nerve is responsible for supplying all thoracic organs and upper 2/3 of abdominal organs?

Answer 19

Vagus (CN X)

Question 20

The right vagus stays posterior to the root of the lungs and descends along the posterior of what structure? Where does the left vagus run?

Answer 20

Right: posterior of the esophagus

Left: posterior to root of lungs, descends along the left lateral surface of the arch of the aorta and descends along anterior of esophagus

Question 21

Answer 21

Question 22

Where do the R/L recurrent larygeal nerves come off of the vagus? and, their position relative to the aorta and its branches?

Answer 22

Question 23

Identify this nerve

Answer 23

Question 24

What are the threee thoracic splanchnic nerves that innervate abdominal organs and their position relative to the vertebrae?

Answer 24

Greater splanchnic: T5-9

Lesser splanchnic: T10-11

Least splanchnic: T12

Question 25

Where does the thoracic duct begin in the abdomen?

Answer 25

Cisterna chyli (level L1-L2)

Question 26

The thoracic duct empties into the junction of which 2 veins?

Answer 26

Left subclavian and left internal jugular vein

Question 27

Indentify these important structures

Answer 27

Question 28

What is chylothorax?

Answer 28

Lymph in a pleural cavity (more than 50% of malignant etiologies)

Question 29

Where does the azygous vein run? What are its two possible branches?

Answer 29

Runs cranially/caudally along the right side of the vertebral bodies

Hemizygos (inferior aspects along left side of the thoracic vertebrae) and accessory hemizygous (superior aspect of the left side of the thoracic vertebrae)

Question 30

What are these three veins?

Answer 30

Question 31

The arch of the azygous vein joins the SVC just superior to what structure?

Answer 31

The hilar region of the right lung

Question 32

What is pancoast syndrome?

Answer 32

An apical brochogenic carcinoma (superior sulcus tumor) that can impinge on adjacent anatomical structures. This can lead to Horner’s syndrome– interruption of sympathetic innervation to head and neck resulting in ptosis (drooping of upper eye lid), myosis (constriction of pupil), and anhydrosis (reduced sweating) unilaterally). Pt may also present w/ neurovascular compromise for the arm with wasting, pain, or paraesthesia of the arm.