Anatomy Flashcards
Anterior mediastinum key points
Potential space
Only really contains thymus
Posterior mediastinum key points
Contains aorta and oesophagus
Everything behind pulmonary trunk
4 rough borders of the heart
Left: mid-clavicular line
Right: parasternal
Top: sternal angle
Bottom: normally no lower than 5th rib
The apex of the heart sits in the:
5th intercostal space
Fibrous pericardium key points
Blends with collagen of diaphragm
innervated by phrenic nerve
Referred pain to brachial plexus areas
Serous pericardium key points
Made of mesothelium
Consists of parietal and visceral pericardium with pericardial cavity between the two
Parietal pericardium innervated by phrenic nerve
Visceral pericardium innervated by sympathetic chain
The base of the heart is at the:
Top
The base of the pericardium is at the:
Bottom
Transverse pericardial sinus
Gap that separates arteries from veins
Useful for bypass surgery
Oblique pericardial sinus
Formed by reflection onto pulmonary veins due to cardiac looping
Underneath transverse pericardial sinus
Specific borders of the heart
Right: right atrium
Bottom: right ventricle
Left: left ventricle and auricle
The coronary sinus is also called:
The atrioventricular groove
Right coronary artery branches from top to bottom
Sinoatrial nodal branch
Marginal branch
Atrioventricular nodal branch
Posterior interventricular branch
Marginal branch supplies:
Right ventricle
Posterior interventricular branch supplies:
Posterior interventricular groove
Left coronary artery branches from top to bottom
Left circumflex branch
Anterior interventricular branch
Left circumflex branch supplies:
Left ventricle and interventricular groove
Venous drainage of heart
Coronary sinus
Posterior, anterior, great, small, middle cardiac veins
Also oblique vein of left atrium
CS pumps blood back into right atrium
Sinus venarum
Smooth muscle wall space of right atrium that veins drain into
Musculi pectinati
Bundles of cardiac muscle arranged in parallel fashion
Valve of inferior vena cava
Channels blood from placenta through foramen ovale before birth
Fossa ovalis
Closed over hole, remnant of foramen ovale
Foramen ovale
Hole between right atrium and left atrium before birth
Tricuspid valve
Atrioventricular
Between right atrium and right ventricle
Right auricle origin
Muscular piece of atrium from primitive atrium
Chordae tendineae
Tethered, but only to inlet valves
With papillary muscles, responsible for pushing AV valve up to close it
Pulmonary valve
Semilunar
3 cusps
Between right ventricle and pulmonary trunk
Moderator band
Also called septomarginal trabecula
Runs from septum, which is the wall between two ventricles, to margin
Only in right ventricle
Allows papillary muscles to contract just before ventricles fully activate
Mitral valve
Bicuspid
Atrioventricular
Between left atrium and left ventricle
Coronary ostia
2 holes right by the cusps of the aortic valve which ascend into left and right coronary arteries
Stenosis
Narrowing of blood vessels
Generates turbulence downstream
Causes noise and potentially regurgitation
1st heart sound
Lub
Generated by inlet valves closing
2nd heart sound
Dub
Generated by outlet valves closing
Best place to hear the mitral valve sound
5th intercostal space medial
Away from bones and other turbulence
Best place to hear the tricuspid valve sound
5th intercostal space
Left edge of sternum
Best place to hear the aortic valve sound
2nd intercostal space, just below sternal angle
Right edge of sternum
Best palce to hear pulmonary valve sound
2nd intercostal space, just below sternal angle
Left edge of sternum
Laminar flow
Normal blood flow
Silent
Velocity occurs in layers, with fastest blood flow in the middle of the vessel
Interventricular septum function
Stiffens before left ventricle contracts to protect right ventricle from the power of the left ventricle
3 nervous supplies of the heart
Somatic
SNS
PSNS
Somatic nervous supply
Phrenic nerve supplies outer pericardium
Pain refers to C3, 4 and 5 which can be felt in the upper shoulder and upper neck
SNS nervous supply
Sympathetic chain
Heart by T1 - T4
Angina felt in the chest, nipple line and running down arms
Functions to increase heart rate, contraction of heart, systemic blood pressure and coronary artery vasodilation
PSNS nervous supply
Vagus nerve
General referred pain, nausea and malaise
Decreases heart rate and systemic blood pressure
Increases coronary artery vasoconstriction
7 structures in the transthoracic plane
Carina Arch of aorta Arch of azygous vein Thoracic duct Cardiac plexus Ligamentum arteriosum Pulmonary trunk bifurcation
Great veins of the thorax
Superior vena cava
Branches into left and right brachiocephalic veins
Each branches off internal and external jugular veins
Both continue as right and left subclavian veins
Branches of the aorta
To the right: Brachiocephalic trunk Branches into right common carotid Continues as right subclavian Branches into right internal thoracic with small anterior intercostal branches To the left: Branches into left common carotid Branches into left subclavian which branches into left internal thoracic with small posterior intercostal branches
Phrenic nerve position
C3 and 4 from cervical plexus
C5 from brachial plexus
Both come through ribcage
Right phrenic nerve around the side of right atrium
Left phrenic nerve around the side of left ventricle
Both give off pericardial branches
Vagus nerve position
Right vagus comes down over right subclavian artery
Branches off into right recurrent laryngeal nerve which loops around right subclavian artery
Left vagus comes down to the left of aorta
Branches off into left recurrent laryngeal nerve which comes around aorta then back up towards neck
Vagus nerves link back into plexus at lower oesophagus which goes on to supply abdominal viscera
Muscle between subclavian artery and subclavian vein
Anterior scalene muscle
Things to consider when inserting a central line
Access Risk of puncture Lungs Risk of bleeding Risk of infection Short or long term placement
4 places you could put a central line
External jugular vein
Internal jugluar vein
Femoral vein
Subclavian vein
Central line in external jugular vein +ves and -ves
\+ve: Easy access Low risk of pneumothorax -ve: Small vessel Uncomfortable for patient
Central line in internal jugular vein +ves and -ves
\+ve: Won't get in the way Easy to find and thread -ve: High risk of carotid artery puncture High risk of pneumothorax
Central line in femoral vein +ves and -ves
\+ve: Fast, easy access No risk of pneumothorax -ve: High risk of infection High risk of embolism
Central line in subclavian vein +ves and -ves
\+ve: Comfortable for patient Good for long term -ve: High risk of subclavian artery puncture High risk of damage to brachial plexus
Azygous vein
When the right superior intercostal vein moves from the superior mediastinum into the thorax it becomes the azygous vein
Past the thorax it is known as the right ascending lumbar vein
Hemiazygous vein
Branches from the azygous around the T8/9 vertebral level and crosses vertebral column to left hand side
Descends down and leaves thorax, becoming ascending lumbar vein
Accessory hemiazygous vein
Branches from the azygous around the T8/9 vertebral level and crosses vertebral column to left hand side
Ascends up, ends around the T4 level
Thoracic duct
Between azygous and hemiazygous veins, exits between left internal jugular vein and left subclavian vein
Valves prevent venous backflow
Gets extra fluid back into blood system
Main lymphatic drainage
Cisterna chylii
Goes over azygous/hemiazygous connections
‘Water reservoir’ of thoracic duct
4 major constrictions of oesophagus
1) junction of oesophagus with pharynx
2) where oesophagus is crossed by arch of aorta
3) where oesophagus is compressed by left main bronchus
4) at the oesophageal hiatus
Aortic coarctation
Diagnosed on a 6 week baby check
Take radial and femoral pulse - should be in sync and same strength
If below left subclavian artery branch it can be fixed by anastamosing posterior and anterior intercostal arteries to resupply legs
Coarctation after branching of left subclavian artery
Radial pulses will be in sync but femoral pulse will be out of sync and weaker
Coarctation before branching of left subclavian artery (after branching of left common carotid)
Left radial pulse will be weaker and out of sync with the right radial pulse
Two anastamoses to alleviate aortic coarctation
Between posterior and anterior intercostal arteries
Between superior and inferior epigastric arteries
Oesophageal arterial supply
Superior: inferior thyroid artery
Middle: branches of the aorta
Inferior: left gastric aftery
Venous drainage of oesophagus
Superior: brachiocephalic trunk
Middle: azygous system
Inferior: left gastric vein
3 areas for portosystemic shunts
Oesophageal varices
Anorectal varices
Caput medusae
Portal hypertension
Cirrhotic liver causes blockages and blood flows back through the portal and gastric veins, joining back up with inferior mesenteric vein and azygous vein
Vessels too small to handle large backflow so they become distended and can rupture
