Mediastinum and 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. Thymus2. Trachea3. Esophagus4. Thoracic duct5. Aortic Arch6. 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- 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 pericardium2. SVC3. Ascending aorta4. Pulmonary trunk5. Right and left pulmonary veins6. Right and left phrenic nerves7. Cardiac plexus8. 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 pericardiumVisceral 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 17

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

Answer 17

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

Question 18

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

Answer 18

Pericardiocentesis

Question 19

What are the contents of the posterior mediastinum?

Answer 19

EsophagusDescending aortaAzygous veinThoracic ductSympathetic chain and splanchnic nerves

Question 20

Explain the course of Esophagus

Answer 20

• 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 21

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

Answer 21

1. Junction of the esophagus with the pharynx2. In the superior mediastinum where the esophagus is crossed by the aortic arch3. In the posterior mediastinum where the esophagus is compressed by the left main bronchus4. In the posterior mediastinum at the esophageal hiatus in the diaphragm

Question 22

Describe the course of descending aorta

Answer 22

• 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 23

What are the branches of descending aorta?

Answer 23

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

Question 24

What is the function of the azygous vein?

Answer 24

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

Question 25

Describe the course of azygous vein

Answer 25

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 26

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

Answer 26

11, 1

Question 27

Where do the posterior intercoastal veins drain to?

Answer 27

1st posterior intercostal vein on each side drain into brachiocephalic veinRemaining right intercostal veins drain into azygous veinRemaining left intercostal veins drain into azygous veins via hemiazygous vein

Question 28

Explain the course of thoracic duct

Answer 28

• 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 29

Where do the splanchnic nerve supply?

Answer 29

Abdominal organs inferior to the diaphragm