CVS-Mediastinum & Pericardium

Question 1

Where is the sternal angle located?

Answer 1

Between T4 to T5 Vertebrae

Question 2

What are the borders of superior mediastinum?

Answer 2

Superiorly, first rib and inferiorly, T4 vertebrae

Question 3

What are the contents of the superior mediastinum?

Answer 3

1. Thymus
2. Trachea
3. Esophagus
4. Thoracic duct
5. Aortic Arch
6. Veins (SVC, Brachiocephalic)
7. Nerves (Vagus, phrenic , left recurrent laryngeal)

Question 4

What is one organ that occupies the superior mediastinum and upper part of the anterior mediastinum?

Answer 4

Thymus

Question 5

What is the function of Thymus?

Answer 5

• Receives blood from the internal mammary artery / internal thoracic artery
• Plays a role in development and maturation of T cells

Question 6

The inferior mediastinum can be divided into ____, ____ and _____

Answer 6

Anterior, Middle and Posterior

Question 7

Where is the location of the middle Mediastinum?

Answer 7

Between anterior and posterior mediastinum

Question 8

What are the contents of the Middle Mediastinum?

Answer 8

1. Heart with pericardium
2. SVC
3. Ascending aorta
4. Pulmonary trunk
5. Right and left pulmonary veins
6. Right and left phrenic nerves
7. Cardiac plexus
8. Lymph nodes

Question 9

The pericardium consists of ____ layers, ______ pericardium and ____ pericardium. The _____ pericardium has ____ layers, the ____ layer and ____ layer.

Answer 9

The pericardium consists of 2 layers, fibrous pericardium and serous pericardium. The serous pericardium has 2 layers, the parietal layer and visceral layer.

Question 10

Describe the fibrous pericardium

Answer 10

It’s the outermost layer, tough and inelastic. It is bounded to the central tendon of the diaphragm by pericardiophrenic ligament.

Question 11

Describe the serous pericardium

Answer 11

Parietal layer: Attaches to fibrous pericardium
Visceral layer (epicardium): Attaches to heart wall

Question 12

Where is pericardial fluid found?

Answer 12

Pericardial space/cavity (10-20ml)

Enables the heart to move and beat in a frictionless environment

Question 13

Which nerve supplies the fibrous pericardium and parietal layer of the serous pericardium?

Answer 13

Phrenic nerve, sensitive to pain

Question 14

Which nerve supplies for the visceral layer of serous pericardium?

Answer 14

Branches of the sympathetic and the vagus nerve, insensitive to pain

Question 15

Explain the course of transverse pericardial sinus.

Answer 15

Located posterior to the ascending aorta and pulmonary trunk, anterior to superior vena cava

Question 16

Explain the course of oblique pericardial sinus.

Answer 16

Bounded laterally by the pericardial reflections and posteriorly by the pericardium overlying the anterior aspect of the esophagus

Question 16

What are the structures that pass through the openings of the diaphragm?

Answer 16

IVC (T8)
Esophagus, Vagus nerve (T10)
Aorta, thoracic duct, azgous vein(T12)

Question 17

(Clinical Anat) What is one procedure performed to drain fluid from the pericardial cavity e.g.cardiac tamponade?

Answer 17

Pericardiocentesis

Question 18

What are the contents of the posterior mediastinum?

Answer 18

Esophagus
Descending aorta
Azygous vein
Thoracic duct
Sympathetic chain and splanchnic nerves

Question 19

Explain the course of Esophagus (IMPTT)

Answer 19

• Continues from the pharynx at C6 vertebrae
• Enters the thoracic inlet and lying anterior to the vertebral body and posterior to the trachea
• At the level of sternal angle, crossed by the aortic arch on the left, arch of azygous vein on the right and left bronchus in front
• Crosses down the posterior mediastinum, lies behind the left atrium
• Pierce the diaphragm at T10 level to join the stomach

Question 20

(IMPTTT) What are the 4 points of esophageal constriction?

Answer 20

1. Junction of the esophagus with the pharynx
2. Where the esophagus is crossed by the aortic arch
3. In the posterior mediastinum where the esophagus is compressed by the left main bronchus
4. In the posterior mediastinum at the esophageal hiatus in the diaphragm

Question 21

Describe the course of descending aorta

Answer 21

• Continuation of arch of aorta and ends as abdominal aorta
• Begins at left side of body of T4 vertebrae but moves midline to lie anterior to lower thoracic vertebrae as it descends in the posterior mediastinum

Question 22

What are the branches of descending aorta?

Answer 22

• Posterior intercoastal arteries
• Esophageal artery
• Bronchial
• Pericardial
• Subcostal
• Mediastinal

Question 23

What is the function of the azygous vein?

Answer 23

Drains blood from the posterior wall of the thorax and abdomen, recieves posterior intercoastal, esophageal, bronchial and mediastinal veins.

Question 24

Describe the course of azygous vein

Answer 24

Ascends in the posterior mediastinum through the aortic opening passing close to the inferior T8 vertebrae on the right and arches on the superior aspect of the root of the right lung to join SVC

Question 25

There are ___ posterior intercoastal veins and ___ subcoastal vein on each side.

Answer 25

11, 1

Question 26

Where do the posterior intercoastal veins drain to?

Answer 26

1st posterior intercostal vein on each side drain into brachiocephalic vein

Remaining right intercostal veins drain into azygous vein

Remaining left intercostal veins drain into azygous veins via hemiazygous vein

Question 27

Explain the course of thoracic duct

Answer 27

• Originates from the cisterna chyli in the abdomen as dilated sac and ascend through the aorta opening in the diaphragm
• In the posterior mediastinum, it lies between the descending aorta and azygous vein
• At T4/T5 vertebrae level, it crosses to the left and posterior to the esophagous and ascends into the superior medistinum
• Empty into the venous system near the venous angle

Question 28

Where do the splanchnic nerve supply?

Answer 28

Abdominal organs inferior to the diaphragm