Middle mediastinum

Question 1

what is the pulmonary circulation?

Answer 1

right heart pumps deoxygenated blood to the lungs

Question 2

what is pressure of pulmonary circulation?

Answer 2

12-16mmhg

Question 3

whats the systemic circulation

Answer 3

left heart pumps oxygenated blood throughout the body

Question 4

whats the pressure in the systemic circulation?

Answer 4

70-120mmHg

Question 5

whats the boundaries of the mediastinum?

Answer 5

two pleural sacs
sternum
CC
thoracic vertebrae

Question 6

where lies the plane which halfs the mediastinum into supeurior and inferior mediastinum

Answer 6

plane passes through sternal angle and T4/5

Question 7

why is mediastinum important?

Answer 7

its highly mobile region allowing volume and pressure changes

Question 8

what does the middle mediastinum contain

Answer 8

heart 
pericardium
origins of great vessels - aorta, pulmonary trunk and venacava 
smaller vessels (pulmonary veins)
phrenic nerves and the vagus nerve

Question 9

right side of the mediastinum

Answer 9

related to right atrium and veins

superior VC
arch of azygous
IVC

Question 10

left side of the mediastinum

Answer 10

related to left ventricle

left common carotid
left subclavian
arch of aorta
thoracic aorta

Question 11

whats the pericardium

Answer 11

fibro-serous sac that encloses heart and roots of the great vessels

Question 12

functions of pericardium

Answer 12

anchors heart to surrounding tissues without compormising cardiac movement

prvents overfilling of the heart

Question 13

what are the 2 layers of the pericardium?

Answer 13

fibrous pericardium (external)
serous pericardium (internal)

Question 14

fibrous pericardium?

Answer 14

external

fuses with adventitia of great vessels

posteriorly =- attached by pericardiovertebral ligaments to the 5th - 8th thoracic vertebrae

Question 15

anterior attachments of fibrous pericardium

Answer 15

anteriorly - attached by sternopericardial ligament to body of sternum and 3rd - 6th costal cartilages

Question 16

posterior attachments of the fibrous pericardium

Answer 16

attached by pericardiovertebral ligaments to the 5th - 8th thoracic vertebrae

Question 17

inferior attachments of the fibrous pericardium

Answer 17

blends with central tendon of the diaphragm (pericardiophrenic ligament)

Question 18

serous pericardium layers

Answer 18

2 layers - parietal and visceral

parietal - lines inner aspect of fibrous pericardium and reflected around roots of great vessels and continues as the visceral layer

visceral layer (around organ) = also known as the epicardium which is attached to the muscles of the walls of the heart

Question 19

where is the pericardial cavity

Answer 19

between parietal and visceral layers of serous pericardium

Question 20

whats the pericardial fluid made from and what does it do?

Answer 20

pericardial fluid is 10-15mL of fluid which is produced by the serous pericardium and reduces friction during contraction of the heart

Question 21

when are the two sinuses formed and how?

Answer 21

during embryological development

the heart tube folds and invaginates into the serous pericardium (within fibrous sac) and forms two sinuses

Question 22

whats the oblique sinus

Answer 22

also known as Haller’s cul de sac

potential space behind the left atrium

Question 23

whats the transverse sinus

Answer 23

also known as sinus of theile
space between the atrial and venous ends of the heart

seperates Aorta and PT from SVC - posterior to ascending aorta and PT and anterior to SVC
superior to LA and pulmonary veins

Question 24

arterial supple to the pericardium

Answer 24

supplied by the pericardiacophrenic artery and the musculophrenic artery

(subclavian artery > internal thoracic artery > pericardo and musculophrenic)

Question 25

thoracic aorta is suppled by

Answer 25

bronchial arteries esophageal arteries superier phrenic arteries

Question 26

visceral layer (epicardium) suppled by

Answer 26

coronary artery

Question 27

venous drainage of the pericardium

Answer 27

azygos vein drains to the SVC | and the pericardiocophrenic vein which drains to internal thoracic vein which drains to brachiocephalic vein

Question 28

lymphatic drainage of the pericardium

Answer 28

tracheobroncial lymph nodes

Question 29

nerve supply of pericardium

Answer 29

phrenic nerve - sensory fibres vagus nerve - vasomotor fibres cardiopulmonary splanchnic nerves (sympathertic)

Question 30

whats the phrenic nerve

Answer 30

branch of the cervical plexus arising from ventral rami of C3,4,5 - keeps the diaphragm alive found in the neck

Question 31

where does phrenic nerve enter superior mediastinum

Answer 31

between venous and arterial planes (subclavian artery and vein) behind clavicle

Question 32

where does phrenic nerve travel in inferior mediastinum

Answer 32

passes anterior to root of lung accompanied by pericardiacophrenic artery and vein lies on either side of the ehart between the fibrous percardium and the pariteal pleura of the lungs

Question 33

pathway of left phrenic nerve

Answer 33

crosses aortic arch anterior to root of left lung over left ventricle

Question 34

pathway of right phrenic nerve

Answer 34

adjacent to SVC then IVC | through caval opening

Question 35

what does phrenic nerve supply

Answer 35

sole motor supply to diaphragm | sensory fibres to parietal pleura, peritoneum and pleura related to central tendon of diaphragm refered pain

Question 36

refered pain of phrenic nerve?

Answer 36

structure with sensory supply via phrenic (pleura, peritoneum and pleura of tendon of diaphragm) can cause refered pain inlateral neck, supraclavicular and shoulder tip due to the supraclavicular nerves C3 and 4 suplying skin over shoulder c4 dermatome

Question 37

phrenic nerve injury

Answer 37

``` cardiac surgery - snstillation of saline slush for myocardial preservation thoracic surgery lung tumors mediastinal tumours polio latrogenic ```

Question 38

apex of the heart

Answer 38

left 5th intercostal space and 8-10cm left of midline more superior and lateral in children

Question 39

base of the heart

Answer 39

left atrium and pulmonary veins (small portion of the right atrium)

Question 40

where is base of heart fixed

Answer 40

posteriorly to pericardium at level of t6(5) - T9(8) vertebrae the oblique pericardial sinus lies posterior to this (left atrium is related to the osophagus)

Question 41

surfaces of heart - sternocostal

Answer 41

anterior right ventricle and small portion of right atrium

Question 42

surfaces of the heart - diaphragmatic

Answer 42

inferior left ventricle and small portion of right ventricle sits on central tendon of diaphragm seperated from base of heart by the coronary sinus

Question 43

right margin of the heart

Answer 43

right pulmonary surface

Question 44

left margin of heart

Answer 44

left pulmonary surface

Question 45

inferior margin

Answer 45

between anterior and diaphragmatic surfaces

Question 46

obtuse margin

Answer 46

between anterior and left pulmonary surfaces

Question 47

what runs in the anterior interventricular sulcus

Answer 47

divides ventricles anterior interventricular artery great cardiac vein (anterior interventricular vein) this is to the RIGHT of the apex of the heart

Question 48

what runs in the coronary sulcus

Answer 48

seperates atria from ventricles right coronary artery left circumflex artery small cardiac vein coronary sinus

Question 49

what runs in the posterior interventricular sulcus

Answer 49

posterior interventricular artery | middle cardiac vein (posterior interventricular vein)