Heart and Great Vessels

  • long axis (L anterior oblique), short axis and four chamber planes
  • base (LA and pulmonary vv), apex (LV), right/anterior border (RV)
  • cardiothoracic ratio on PA <50% (<55% in asian and afro-caribbean, <60% in infants)

Pericardium (1-2mm)

  • fibrous pericardium >central tendon diaphragm (pericardiophrenic lig), sternum (sternopericardial lig), roots of great vessels (aorta, PT, SVC)
    • common sheath around aorta and pulmonary trunk for 2-3cm
  • serous pericardium
    • visceral pericardium = epicardium
    • parietal pericardium (firmly adhered to fibrous pericardium)
  • epicardial fat (betw myocardium and epicardium)
  • pericardial fat pads (betw pericardium and pleura)

Pericardial Sac and Sinuses

  • 25mL pericardial fluid
  • transverse sinus (betw aorta, PT, atria, SVC)
    • superior aortic recess (ant, posterior and right lateral portions; > aortopulmonary window recess anterior to aorta and PA)
    • right and left pulmonic recesses (betw pulmonary aa and vv; ligament of Marshall [remnant of L SVC])
    • inferior aortic recess (betw ascending aorta and SVC/RA)
  • oblique pericardial sinus (betw LA, oesophagus, IVC, pulmonary vv)
  • postcaval recess (P/R to SVC, R lateral extension of superior aortic recess)
  • right and left pulmonary venous recesses (betw superior and inferior pulmonary vv)


  • A = pleura, anterior chest wall (2nd-6th costal cartilages, sternum
  • P = descending aorta, oesophagus, trachea, bronchi, vertebrae
  • S = lung hila, great vessels
  • I = diaphragm
  • lat = lungs, pericardiacophrenic a+v, phrenic nn

Vessels and Innervation

  • pericardiacophrenic artery (<IMA)
  • phrenic n (C3-5)
  • musculophrenic aa (<IMA)
  • descending thoracic aortic branches
  • pericadiacophrenic vv > innominate, azygos or subclavian vv
  • visceral pericardium < coronary circulation, vagus n
  • lymph > parasternal, diaphgragmatic and para-aortic nodes

Heart Chambers

Right Atrium (RA)

  • pressure 2-5mmHg, sats 65-75%, EDV 57mL
  • right auricular appendage (anteromedial)
  • musculi pectinati (R wall)
  • crista terminalis (betw pectinati and smooth wall)
  • interatrial septum (left anterior oblique plane)
  • fossa ovalis
  • limbus of fossa ovalis (edge)
  • torus aorticus (prominent part sup-ant from sinus and aortic valve)
  • SVC, IVC and coronary sinus (adj to IVC) openings
  • anterior cardiac vein openings
  • Eustachian valve (of IVC)
  • Thebesian valve (of coronary sinus)
  • tricuspid valve (L anterior)
  • patent foramen ovale (V10%)

Right Ventricle (RV)

  • pressure 25mmHg systolic, 0-5mmHg diastolic (PA 25/10 mmHg), EDV 165mL, EF 45-55%
  • interventricular septum (L anterior oblique plane)
  • trabeculae carneae
  • conus arteriosus = infundibulum of the outflow tract (prominence separating muscular inflow and smooth outflow tracts)
  • crista supraventricularis = supraventricular crest (betw trabeculae and conus)
  • septomarginal trabecula (septal limb > moderator band) > anterior papillary muscle
  • tricuspid valve (fibrous atrioventricular ring)
  • chordae tendinae
  • ant, posterior and septal/medial cusps and papillary mm
  • pulmonary valve (left anterior [anterior], right anterior [right] and posterior [left] cusps; most sup-ant valve)

Left Atrium (LA)

  • pressure 2-8mmHg (same as pulmonary capillary wedge pressure), sats 94%, EDV 50mL
  • left and right pulmonary veins
  • mitral valve (left inferior anterior)
  • left auricular appendage
  • cor triatriatum (V, fibromuscular septum with opening between common pulmonary v and LA)

Left Ventricle (LV)

  • pressure 120mmHg systolic, 0-5mmHg diastolic (aorta 120/80mmHg), stroke volume (SV) 70mL, cardiac output (CO) 4-5L/min, ejection fraction (EF) 50-75%, end-diastolic volume (EDV) 125-150mL
  • fibrous ring of mitral and aortic valves
  • fine trabeculae
  • cardiac apex
  • (bicuspid) mitral valve
  • anterior (medial) and posterior cusps and papillary mm
  • aortic valve (anterior [right coronary], left posterior [left coronary] and right posterior [noncoronary] cusps)
  • sinuses of Valsalva

Valves on XR

  • on lat, M and T lie just inferior to line of ant-inf T5 to apex of heart
  • T most R-inf-ant
  • M just superior to T, most post
  • A just superior to M
  • P sup-L to A, most sup-L

Conducting System

Sinus Node (15 x 3mm)

  • sulcus terminalis (R of SVC)
  • anterior internodal tract (ant interatrial septum> LA)
  • middle internodal tract (post septum)
  • posterior internodal tracts (crista terminalis and posterior septum)

Atriventricular Node

  • med floor RA between septal leaflet and coronary sinus
  • bundle of His = atrioventricular bundle (>betw right/anterior and noncoronary cusps)
  • right and left bundle bundles
  • Purkinje fibres = subendocardial branches

Coronary Circulation

Right Coronary Artery (RCA)

  • anterior/right sinus of Valsalva > AV groove
  • conus artery (ostium> pulmonary outflow tract)
  • sinus artery (anticlockwise around SVC>SA node)
  • atrial branches
  • acute/right marginal branches (> RV)
  • crux = junction AV groove and posterior IV septum
  • AV nodal branch
  • posterior descending/interventricular artery (PDA;> posterior 2/3 interventricular septum, inferior LV)
  • inferior surface = posterolateral LV branches

Left (Main) Coronary Artery (LCA)

  • left posterior sinus of Valsalva
  • LCA bifurcation (within 1cm)
  • left anterior descending artery (LAD)
    • septal branches (>ant 1/3 of septum)
    • diagonal branches
    • branch to RV (occasionally)
  • left circumflex artery (LCx, AV groove)
    • obtuse/left marginal branches (>lat LV)
    • posterolateral branch
    • atrial branches (>post and lateral LA)

Coronary Variations

anomalies of origin

  • high take-off
  • LAD and LCx arising from separate ostia (0.41%)
  • conus artery from the coronary sinus
  • single coronary artery
  • anomalous origin of the coronary artery from the pulmonary artery (ALCAPA)
  • RCA or LCA from opposite coronary sinus (retroaortic, interarterial [betw ao and PA], prepulmonic or septal/subpulmonic)
  • LCx or LAD from right coronary sinus
  • LCA or RCA from noncoronary sinus

anomalies of course/branching

  • right coronary dominance in 85%
  • PDA from circumflex (left dominance in 10-15%)
  • no PDA, supply from marginal branches or elongated LAD
  • double PDA (early origin proximal to crux)
  • trifurcation of LCA with ramus medianus = intermediate artery (> anterior LV)
  • LAD taper before apex (20%), septal branch runs parallel or PDA curves around apex
  • double LAD (long branch from LCA or RCA and courses apex)
  • sinus artery from left circumflex (40%)
  • AV nodal branch from circumflex (10%)
  • myocardial bridging (usually mid LAD)

Coronary Veins

  • coronary sinus (post AV groove)
  • great cardiac vein (ant IV > L AV groove)
  • < left marginal vein
  • oblique vein of left atrium (>coronary sinus)
  • middle cardiac vein (post IV groove > sinus)
  • small cardiac vein (R AV groove > sinus)
  • left posterior ventricular vein (> sinus)
  • anterior cardiac veins (over RV > RA directly)
  • venae cordis minimae (in myocardium> chambers)

Thoracic Aorta

  • fixed at valve, main branches, isthmus, intercostal aa
  • aortic root (~3cm, T5 covered by pericardium), ascending (~5cm x 35mm), arch (T4), descending (25 mm)
  • brachiocephalic/innominate artery (>R subclavian and common carotid aa)
  • left common carotid artery (L CCA)
  • left subclavian artery (L SCA)
  • isthmus of aorta (junction of arch and descending aorta; fixed)
  • ligamentum arteriosus (left main pulmonary artery > isthmus)
  • posterior intercostal arteries (9 pairs>3rd -12th intercostal grooves)
  • 2 left bronchial arteries
  • oesophageal branches (≤5)
  • radiculomedullary arteries (2-3)
  • mediastinal branches
  • superior phrenic arteries (2)
  • pericardial branches (>post pericardium)
  • subcostal arteries (2)


  • A ascending = sternum, R lung, thymus; arch = L superior interocstal v, L innominate vein; descending = L phrenic nerve, L lung, L main bronchus, diaphragm
  • P arch = trachea, T4, oesophagus; P descending = vertebrae, hemiazygos v
  • R descending = oesophagus, trachea, thoracic duct, azygos v, R lung
  • S arch = aortic branches, L brachiocephalic v
  • I arch = ligamentum arteriosum, L recurrent laryngeal n, pulmonary trunk, L main bronchus

variants (N in only 65%)


  • left vertebral a from arch (5%, between L CCA and L SCA, or distal to L SCA)
  • bilateral brachiocephalic trunks (2.7%)
  • ‘bovine’ arch (2.5%, LCCA from brachiocephalic)
  • aberrant R SCA (0.5%, distal to LSCA > posterior to oesophagus)
    • diverticulum of Kommerell (dilatation of proximal aberrant SCA
  • separate origins of R CCA and R SCA
  • late branching of brachiocephalic or early branching of L CCA hence crossing anterior to trachea (may cause compression)
  • ICA and ECA directly from arch (ie no CCA on one/both sides)
  • thyroidea ima, bronchial aa, inferior thyroid, or IMA from arch


  • double arch (L&R vessesls from diff arches, around oesophagus/trachea)
  • right-sided arch type 1 (mirror image)
  • right-sided arch type 2 (aberrant L SCA)
  • cervical aortic arch (usually with R arch)

Great Veins

  • right and left brachiocephalic/innominate vv < internal jugular, subclavian, internal thoracic/mammary, inferior thyroid (L), supreme intercostal, L superior intercostal, thymic veins)
    • R: A = medial clavicle, R manubrium; P/med = brachiocephalic a
    • L: A = manubrium; P = L CCA, L SCA
  • superior vena cava (SVC; 7cm; 1/3-2/3 di of asc.aorta; junction lower 1st costal cartilage with manubrium > 3rd costal cartilage)
    • azygos v (post SVC just above pericardial sleeve)
    • A = thymus, R pleura/lung
    • P = R bronchus, R PA, R superior pulmonary veins
    • R = phrenic n, pericardiophrenic vessels, R lung, R IMA
    • L = ascending aorta
  • inferior vena cava (IVC, few cm in thorax)
  • persistent left SCV (V0.3-0.5%, > coronary sinus)