Cardiovascular anatomy Flashcards
Name the layers of the pericardium
Fibrous
Parietal
Visceral
Describe the attachments of the fibrous layer of the pericardium to surrounding structures
Superior - great vessels
Anterior - sternum
Inferior - central tendon of the diaphragm
What is the function of the pericardium?
Stabilize the heart within the thorax whilst permitting free movement of the heart within the pericardial sac during filling and ejection.
What is a normal cardiothoracic ratio, how is it calculated and what can causes normal distortion of this ratio
< 50%
Maximal transverse diameter of the heart divided by maximum internal diameter of the thorax
Distortion: AP views
Increased intrathoracic pressure
What three structures drain into the right atrium
Superior vena cava
Inferior vena cava
Coronary sinus
Name the cusps of all the heart valves
TRICUSPID
Septal
Anterior
Posterior
They attach to the fibrous AV ring superiorly and inferiorly to the chordae tendinae which connect them to papillary muscles connected to the ventricular wall
MITRAL
Anterior
Posterior
Aortic
Left
Right
Posterior
Pulmonary
Left
Right
Anterior
Why does the RV appear crescentic in shape
The LV bulges into the RV
What is the moderator band in the RV
This is a trabeculae (one of many in the trabeculated muscle wall of the RV) that crosses the RV cavity and carries part of the RV conducting system.
What is the smooth walled RV outflow tract called
Infundibulum
In what % of adults can a “probe patent” foramen ovale be found?
15%
Where do the pulmonary veins drain into the left atrium
Posterior wall of LA
How many leaflets does the mitral valve contain and name these
2
Anterior leaflet
Posterior leaflet
In what % of people is the SA node supplied by the RCA
65%
How many internodal tracts exist between the SA node and the AV node, name these
Anterior internodal tract
Middle internodal tract
Posterior internodal tract
What is the function of the AV node
Delay conduction from atria to ventricles
The A-V node is the only electrical link
Abnormal pathways may be responsible for re-entrant tachycardias
In what percentage of people is the AV node supplied by the RCA
80%
Describe the origin course and main branches of the right coronary artery
Origin: Right aortic sinus –> descends in the AV groove –> gives off right marginal artery –> continues to wrap around to the posterior aspect of the heart and gives rise to the posterior interventricular artery as it descends into the posterior interventricular groove
Describe the origin course and main branches of the left coronary artery
Origin: left aortic sinus
divides into the left anterior descending artery (or L. inter-ventricular a.) and left circumflex arteries - the latter giving rise to the left marginal arteries.
LAD gives off septal and diagonal branches
Which parts of the heart re supplied by the left anterior descending artery?
Anterior parts of the left and right ventricles
Anterior 2/3rds of the interventricular septum
What is right dominance with regard to the coronary circulation
When the posterior descending artery arises from the right coronary artery - true in 85% of people
In what percentage of people does the left circumflex artery give rise to the posterior descending artery?
15% = left dominance
What % of coronary blood drains into the coronary sinus and where is the coronary sinus
75% of blood - located in the left AV groove on the posterior aspect of the hear adjacent to the left circumflex.
The Great, Middle and small cardiac veins drain into the carotid sinus
Which veins drain the anterior aspect of the RV
anterior cardiac veins which drain directly into the RA.
What are thebesian veins
Small veins that drain directly into the cardiac chambers
How does the PSNS innervate the heart and what are the basic effects
The vagus and recurrent laryngeal nerve send branches via the deep and superficial cardiac plexuses.
Post ganglionic fibres pass to the SA node and the AV node with minimal distribution to the ventricles..Reduces rate and force of contraction and causes coronary vasoconstriction.
Afferent fibres concerned with cardiac reflexes carried by vagus nerves
Where does SNS supply to the heart arise and what are the effects on the rate and force of contraction?
From the lateral horns of the spinal cord T1 - T4. The pre-ganglionic fibres travel to the three cervical ganglia and the upper thoracic sympathetic ganglia.
Increase heart rate and force of contraction
Which ANS nerves do pain fibres travel with
SNS fibres.
The pain fibres travel from the pain receptor to the spinal cord. Might explain why cardiac pain may be referred to the arm or neck.
What is the contents of the carotid sheath
Common and internal carotid artery
Internal jugular vain
Vagus nerve
The vein is usually lateral to the artery
How is the left subclavian vein different to the right subclavian vein
The thoracic duct drains into the left subclavian vein
What is the origin and course of the left subclavian vein
Continuation of the left axillary vein passes over the first and second ribs and under the left clavicle until meeting the left external and then internal jugular veins which form the left brachiocephalic vein which subsequently flows into the superior vena cava.
Name the boundaries of the femoral triangle
Inguinal ligament (superior) Sartorius muscle (lateral) Adductor longus muscle
How is the femoral vein located for cannulation
In the midline of the femoral triangle and at the midpoint between the symphasis pubis and the ASIS is the femoral artery.
The mnemonic NAVVAN describes the relationship of the nerves, arteries and veins from wither side - the veins are most medial.
Find the medial aspect of the femoral a. pulsation
What are PICC lines
Peripherally inserted central catheters –> inserted via the basilic vein or the median cubital vein.
A valve in the cephalic vein as it drains into the axillary vein makes this less reliable for PICC insertion
What % of the population have a superficial ulnar artery and what is the clinical relevance of this?
2% of the population.
The superficial ulnar artery lies superficial to the bicipital aponeurosis and immediately adjacent to the median cubital vein –> HIGH RIISK FOR INADVERTANT INTRA-ARTERIAL INJECTION
What test must be done before arterial cannulation?
Which arteries can be used for arterial cannulation?
Allen’s test to ensure collateral flow
Radial and ulnar arteries
Dorsalis pedis artery also commonly used for a-line insertion
Large calibre end arteries may also be used (femoral/axillary)
Brachial artery must be avoided!
