Mediastinum & superficial anatomy of the heart pt.2 Flashcards
The____________________ lies between the brachiocephalic trunk and right brachiocephalic
vein.
Right vagus nerve
How does the right vagus nerve descend?
Descends posteriorly towards trachea and crosses the lateral surface of the trachea passing posterior to the oesophagus.
List the branches of the right vagus nerve
Cardiac plexus
Pulmonary plexus
Oesophageal plexus
Which nerve lies posterior to the left brachiocephalic vein, between left common
carotid and left subclavian arteries?
Left vagus nerve
Describe the course of the left vagus nerve
Lies deep to parietal pleura, crosses left side of arch of aorta, passing posterior to root of the left lung.
List the branches of the left vagus nerve
Cardiac plexus
Pulmonary plexus
Oesophageal plexus
Name the branch of the left vagus nerve
Left recurrent laryngeal nerve
Where does the left recurrent laryngeal nerve arise?
At the inferior margin of the aortic arch, lies lateral to ligamentum arteriosum
Passes inferior to arch of aorta, entering groove between trachea and oesophagus.
Describe the right phrenic nerve
Enters mediastinum lateral to vagus nerve.
Lies posterolateral to the right brachiocephalic vein and continues along right side of SVC.
Descends along right side of pericardial sac within the fibrous pericardium, anterior to the root of the right lung.
The right phrenic nerve passes through the diaphragm at the______________________
Caval opening
Describe the left phrenic nerve
Enters mediastinum lateral to the left vagus nerve.
Lies posterolateral to the left brachiocephalic vein.
Passes superficially to the left vagus nerve and left superior intercostal vein.
Follows the left side of the pericardial sac and lies anterior to the root of the left lung.
Where does the left phrenic nerve pierce the diaphragm?
Near the apex of the heart
Name the layers of the pericardium
Fibrous pericardium
Serous pericardium (divided into visceral and parietal percardium)
What is the space between the two layers of the serous pericardium?
pericardial cavity
Describe the fibrous pericardium
Tough connective tissue outer layer.
Cone-shaped bag, apex is continuous with adventitia of great vessels
How is the heart able to retain its position in the mediastinum, and limit distention?
It retains its position due to the attachment of its base to the central tendon of the diaphragm, and its attachment to the sternum via the sternopericardial ligaments
The pericardial sac helps limit cardiac distention
What innervates the fibrous pericardium?
Phrenic nerves pass through and innervate fibrous pericardium, with pericardiophrenic vessels.
What is the importance of the serous fluid?
Allows for uninhibited movement of the heart
T/F: The parietal layer is continuous with the visceral layer at the apex of the heart
F
Parietal layer continuous with visceral layer around roots of great
vessels.
T/F: Parietal layer lines the fibrous pericardium. Visceral layer is adherent to the heart.
T
Describe the superior and posterior reflections of the serous pericardium
Superiorly – surrounds aorta and pulmonary trunk.
Posteriorly – surrounding veins (IVC and Pulmonary veins)
What is another name for the cul-de-sac (zone of relfection around veins?
Oblique pericardial sinus
What is the passage between the two zones of relfection, and where does it lie?
TRANSVERSE PERICARDIAL SINUS
Lies posterior to ascending aorta and pulmonary trunk
Anterior to superior vena cava
Superior to left atrium
List the arterial supply of the pericardium
Internal thoracic artery
Pericardiophrenic, Musculophrenic and Inferior phrenic arteries
Thoracic aorta
List the venous drainage for the pericardium
Azygos system of veins
Superior phrenic vein
Internal thoracic vein
List the nerves that supply the pericardium
Vagus and Phrenic nerves
Sympathetic trunks
Describe the coronary sulcus
Encircles the heart.
Separates atria from ventricles.
List the contents of the coronary sulcus
Right coronary artery
Small cardiac vein
Coronary sinus
Circumflex branch of left coronary artery
Describe the anterior interventricular sulcus as well as its contents
On anterior surface of heart.
* Contains anterior interventricular artery and
great cardiac vein.
Describe the posterior interventricular sulcus as well as its contents
On diaphragmatic surface of heart.
* Contains posterior interventricular artery and
middle cardiac vein.
The________________ is contained within pericardial sac, covered by visceral layer of serous
pericardium – associated with ascending aorta in the same sheath.
pulmonary trunk
Where does the pulmonary trunk arise?
Arises from conus arteriosus of the right ventricle at the opening of
the pulmonary trunk. Slightly anterior to aortic orifice.
How does the pulmonary trunk ascend?
Ascends, moving posteriorly.
* Initially anterior and then to the left of the aorta.
At what level does the pulmonary trunk divide to give off pulmonary arteries?
At the level of T5/T6 intervertebral disc
Where is the right pulmonary artery positioned?
– Posterior to ascending aorta and SVC.
Where is the left pulmonary artery positioned?
Anterior to descending aorta, inferior
to arch of aorta.
Where does the ascending aorta originate?
Originates at aortic orifice at base of left ventricle, level of lower edge of 3rd costal cartilage.
The ascending aorta continues to level of ______________________________ where it enters superior mediastinum to become arch of aorta.
2nd costal cartilage
Describe the aortic arch (its beginning and course)
Begins as ascending aorta emerges from pericardial sac.
* Courses superiorly, posteriorly and to the left.
Where does the aortic arch end?
Ends at T4/T5 vertebral level.
* Extends as high as the manubrium of the sternum.
How is the aortic arch related to the trachea?
Initially anterior and then lateral to the trachea.
What is the first branch of the aorta?
Brachiocephalic trunk. It is the most anterior branch
At what point does the brachiocephalic trunk divide?
At the level of the sternoclavicular joint
Name the divisions of the brachiocephalic trunk and what each division supplies
- Right Common Carotid artery – head and neck
- Right Subclavian artery – right upper limb
Name the second branch of the aortic arch as well as what it supplies
Left common carotid artery
Ascends on the left of the trachea.
* supplies left side of head and neck
What is the 3rd branch of the arch of aorta, and what does it supply?
Left subclavian artery
Ascends on the left of the trachea.
* Left upper limb
What was the importance of the ductus arteriosus in embryological development, and what is the name of its remnant?
Ductus arteriosus connected the pulmonary trunk and the arch of the aorta and allowed blood to bypass the lungs during development.
* Closes soon after birth and forms the ligamentum
arteriosum.
How does the superior vena cava begin?
Begins by union of the right and left brachiocephalic
veins and drains into the right atrium.
Which part of the SVC is incased in the pericardial sac?
The lower part
The SVC passes through the fibrous pericardium at the level of ___________________________
2nd costal cartilage
The SVC receives Receives _____________ vein immediately before entering the pericardial sac
azygos
The IVC enters the pericardium at the level of___________
T8
What veins join to form the IVC? At what verterbral level does this occur?
Formed at L5 by the union of the right and left common iliac veins.
How does the IVC ascend?
Ascends anterior to the vertebral column, on the right side of the abdominal aorta.
What nerve passes through the autopulmonary window? (between the aorta and pulmonary artery)
Left recurrent laryngeal nerve
What would happen if the left recurrent laryngeal nerve would be compressed by a mass in this region?
left vocal cord paralysis and hoarseness of voice
What is the condition in which there is excess fluid in the pericardial cavity?
Pericardial effusion
Explain how pericardial effusion can result in cardiac temponade (heart compression) and biventricular failure
Since fibrous pericardium is “fixed” it cannot expand easily.
* Therefore, an increase in fluid within the pericardial sac would compress the heart – resulting in cardiac tamponade.
* This results in biventricular failure
How is pericardial effusion managed?
Fluid removed with needle to relieve symptoms.
Explain aortic arch anomalies
Normal aortic arch courses to the left of the trachea and passes over left main bronchus.
* A right-sided aortic arch occurs when the vessel courses to the right of the trachea and passes over right main bronchus.
What is dextocardia?
right-sided heart
What is the name of the condition in which there is left-to-right inversion of body’s organs?
Situs inversus
