W01L05 The Mediastinum

Question 1

Pericardium

Answer 1

Fibrous and serous layers

Surround the heart so that i can move, expand and contract, support and stabilize

Question 2

Serous Layer

Answer 2

2 Layers: parietal and visceral layer

Providing a potential space for the heart to beat

Question 3

Fibrous Pericardium

Answer 3

Defines the middle mediastinum

Surrounds the heart and great vessels

Question 4

Attachment of the fibrous pericardium

Answer 4

Closed sac attached superiorly to the roots of the great vessels and inferiorly to the central tendon of the diaphragm

Question 5

Sensory of the pericardium and referred pain

Answer 5

The phrenic nerves lie on either side of the sac and provides its sensory innervation
Referred pain to shoulder tip

Question 6

Cardiac tamponade

Answer 6

Excess fluid in the pericardium restricts the beating of the heart, resulting in heart failure

Question 7

Percarditis

Answer 7

Painful inflammation of the pericardium

Question 8

What halts descent of the diaphragm during inspiration?

Answer 8

Attachment of pericardium to the central tendon of the diaphragm

Question 9

Serous Pericardium

Answer 9

Parietal layer attached to the fibrous layer
Visceral layer attached to the surface of the heart
2 layers are continuous around the roots of the great vessels
Film of lubricating fluid between the visceral and parietal layers

Question 10

2 Pericardial folds

Answer 10

Oblique sinus

Transverse sinus

Question 11

Oblique pericardial sinus

Answer 11

Posterior to the heart

Behind the left atrium

Question 12

Transverse pericardial sinus

Answer 12

Separates the arterial and venous ends of the heart tube
Anterior - aorta and pulmonary trunk
Posterior - SVC and left auricular appendage of left atrium
Used in cardiac surgery

Question 13

Pulmonary circulation

Answer 13

Right heart pumps deoxygenated blood to the lungs

Low pressure 12-16 mmHg

Question 14

Systemic circulation

Answer 14

Left heart pumps oxygenated blood throughout the body system

High pressure 70-120 mmHg

Question 15

Heart surfaces and borders

Answer 15

Sternocostal (anterior) -RV
Diaphragmatic (inferior) - LV
Base (posterior) - LA
Right border - RA
Left border - LV
Apex

Question 16

Apex location

Answer 16

5th left intercostal space, mid-clavicular line

Question 17

Surface markings of the 4 “corners” of the heart

Answer 17

3cc
2cc
6cc
Apex

Question 18

Structures on the right side of the mediastinum

Answer 18

SVC
Arch of the azygos
Right atrium
IVC

Question 19

Structures on the left side of the mediastinum

Answer 19

Left common carotid artery
Left subclavian artery
Arch of aorta
Thoracic aorta
Left ventricle

Question 20

Phrenic nerve

Answer 20

Arise from cervical nerves C3,4,5
Enter the superior mediastinum between the venous and the arterial planes
Pass between the fibrous pericardium and the parietal pleura
Right phrenic related to veins
Left phrenic related to arteries

Question 21

Phrenic nerve motor and sensory supplies

Answer 21

Sole motor supply to diaphragm
Sensory from central tendon of diaphragm, mediastinal parietal pleura and pericardium
Referred pain to the shoulder tip (C4 dermatome)
e.g. rupture spleen has referred pain to left shoulder

Question 22

Pericardial nerve supply

Answer 22

Phrenic nerve C3,4,5

Pain from pericardium may be referred to skin over the shoulder tip

Question 23

Constrictive pericaditis

Answer 23

Abnormal thickening of the pericardial sac can compress the heart
Has Kussmaul’s sign

Question 24

Kussmaul’s sign

Answer 24

Paradoxical rise in jugular venous pressure (JVP) on inspiration. It can be seen in some forms of heart disease and is usually indicative of limited right ventricular filling due to right heart failure.