1.2.1 Mediastinum

Question 1

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

Answer 1

Internal jugular vein and subclavian vein

Question 2

Describe the subdivisions of the medistinum.

Answer 2

Superior: sits above the sternal angle of louis

Inferior: subdivided into anterior, middle, and posterior

Middle: includes heart and pericardium

Question 3

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

Answer 3

Trachea and vertebral column

Question 4

Identify this nerve

Answer 4

Question 5

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

Answer 5

The diaphragm

Question 6

Where does the thoracic duct begin in the abdomen?

Answer 6

Cisterna chyli (level L1-L2)

Question 7

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

Answer 7

Trachea just anterior to esophagus

Question 8

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

Answer 8

Left subclavian and left internal jugular vein

Question 9

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

Answer 9

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

Question 10

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

Answer 10

Vagus (CN X)

Question 11

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

Answer 11

Question 12

What is chylothorax?

Answer 12

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

Question 13

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

Answer 13

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 14

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

Answer 14

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 15

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

Answer 15

The sternal angle or ~T4-T5

Question 16

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 16

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 17

What is the 8-10-12 rule?

Answer 17

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 18

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

Answer 18

SVC, trachea, and occasionally other mediastinal structures

Question 19

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

Answer 19

The hilar region of the right lung

Question 20

What are these three veins?

Answer 20

Question 21

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

Answer 21

T7-10 anteriorly,

T11-12 posteriorly

reffered to cervial levels C3-5 due to phrenic innervation

Question 22

What are the first three branches off of the aorta?

Answer 22

Just remember your ABCS!

A - Arch of Aorta

B - Brachiocephalic

C - Left Common carotid

S - Subclavian

Question 23

What are the 3 parts of the thoracic aorta?

Answer 23

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 24

From which arteries does the thymus recieve its arterial supply?

Answer 24

inferior thyroid and anterior intercostals

Question 25

Indentify these important structures

Answer 25

Question 26

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

Answer 26

Greater splanchnic: T5-9

Lesser splanchnic: T10-11

Least splanchnic: T12

Question 27

What is pancoast syndrome?

Answer 27

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.

Question 28

The phrenic nerve arises from which ventral rami?

Answer 28

C3, C4, C5

Question 29

Identify the three structures.

Answer 29

Question 30

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

Answer 30

Question 31

Answer 31

Question 32

In what region of the mediastinum is the thymus located?

Answer 32

Anterior part of the superior mediastinum