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THORAX VIVASX-Ray: Chest2011-2, 2010-2, 2008-2, 2007-1, 2005-1, 2003-1Outline the structures that make up the right and left cardiomediastinal borders on this X-RayRight Left- Right brachiocephalic vein - Left subclavian artery / left brachiocephalic vein - Superior vena cava - Aortic arch - Right pulmonary trunk - Left pulmonary trunk - Right atrium - Left atrial appendage - Inferior vena cava - Left ventricleWhich corresponding part of the lungs lie adjacent to the right and left cardiomediastinum 2011-2Right upper mediastinum- right superior lobeRight heart border- right middle lobeLeft upper mediastinum- left superior lobeLeft heart border- left superior lobe (lingula segment)Which part of the heart lies immediately behind the sternum (Prompt : What forms the anterior surface of the heart)RV(RA)In the supine position, which mediastinal structures are located at the same level as the sternal angle. (Prompt: What mediastinal structures would you see if you looked at a transverse slice though the chest at the level of T4-5?) 2010-2Mediastinal structures at the transverse thoracic planeCarina (bifurcation), Division of pulmonary trunk, Reflection of the pericardium, SVC (enters R atrium), Hila of the lungs, Transverse fissure of R lung, Ascending aorta becomes arch, Arch becomes descending Aorta, Phrenic nerve, Vagus nerve, L recurrent laryngeal nerve origin Azygos vein, Thoracic duct (crosses from R to L), Pleura approaches the midline anteriorly, OesophagusPlease describe the surface anatomy of the heart. 2008-2Left 2nd costal cartilageRight 3rd costal cartilageRight 6th costal cartilage5th Inter-costal space in left midclavicular line about 9cm from the midlineHas about 1/3 to the right of the midsternal line and 2/3 to the leftPoint to diaphragms: Ask: what is this structure, and what are its attachments? 2008-2, 2007-1Diaphragm is a musculotendinous partition separating the thoracic and abdominal cavities, and is the chief muscle of respiration (inspiration). It has a trifoliate aponeurotic central tendon attached to the IVC and pericardium but no boney attachments – it is completely surrounded by the muscular part that is divided into 3 parts based on peripheral attachments:Sternal part: 2 muscular slips to posterior aspect of the xiphisternumCostal part: Internal surfaces of 7th -12th (inferior 6) costal cartilagesLumbar part: Arises from medial and lateral arcuate ligaments, and the (L) and (R) crura centrally:Medial arcuate is thickening of psoas fascia, from L1/L2 vertebrae to a ridge on transverse process of L1Lateral arcuate ligament starts from L1 transverse process and goes to 12th rib lat to quadratus lumborum (covering this muscle)Crura: (R) is fixed to upper 3-4 lumbar vertebrae and discs between, (L) is attached to upper 2-3, (R) crus fibres slope up to (L) and surrounds the oesophagus (as the hiatus)Median arcuate ligament is fibers from medial edge of each crus that unite with each other in front of aorta at T12, and with the crura form the aortic hiatusWhat are the openings in the diaphragm 2007-1OpeningLocationTransmitsAorticT12 in midlineAorta, thoracic duct, azygos veinOesophagealT10 2.5cm to (L)Surrounded by sling from (R) crusOesophagus, vagal trunks (ant and post), (L) gastric vessels, lymphaticsCavalT8 just to (R)IVC (attached – aids return), (R) phrenic nerveOther smallerSplanchnic nerves, sympathetic trunk, subcostal nerve and vessels, (L) phrenic, neurovascular bundles of 7-11 intercostal spaces, superior epigastric vesselsWhat is the nerve supply of the diaphragm? 2008-2Phrenic nerves (C3-5): Entire motor supply via (L) and (R) to corresponding side of the diaphragm from the inferior surface. Sensory innervation also mostly from the phrenic, but the periphery (costal portion) also from the lower 6-7 intercostal and the subcostal nerves. How does contraction of the diaphragm result in ventilation of the lungs? 2008-2With inspiration contraction causes descent of the central part (periphery is attached)The domes flattenResults in decrease in intrathoracic (and pleural) pressure -> lungs inflate Diaphragmatic contractions responsible for 75% of inspiratory respiratory muscle actionMuch of expiration is passive recoil, so the diaphragm is considered the chief muscle of respirationNote paradoxical movement seen with paralysis (i.e. phrenic nerve injury) – the affected dome will rise with inspirationAlso there is a slight rise in intra-abdominal pressure, and opening of the IVC (via is attachment at the caval opening) – this mechanism aids central venous returnMnemonic: AOC = 12,10,82008-1Describe the intercostal musclesMuscleSup. AttachInferior AttachInnervationMain ActionLevator costarumTransverse processes of T7-11Subjacent ribs between tubercle and anglePosterior primary rami of C8-T11 nervesElevate ribsExternal intercostalInferior border of ribsSuperior border of ribs belowIntercostal nerveElevate ribs during forced inspirationInternal intercostalInterosseous part: depresses ribsDuring active (forced) respirationInnermost intercostalInterchondral part: elevates ribsSubcostalInternal surface of lower ribs near their anglesSuperior borders of 2nd or 3rd ribs belowProbably act in same manner as internal intercostal musclesTransversus thoracisPosterior surface of lower sternumInternal surface of costal cartilages 2-6Weakly depress ribs (Proprioception?)External intercostal: from tubercles of ribs posteriorly to costochondral junction (thence external intercostal membrane) run infero-anteriorly and are most active during inspiration (to increase tonus of intercostal space) and during forced inspirationInternal intercostal: deep to and at right angles to externals from sternum to angle of ribs posteriorly (continued posteriorly as internal intercostal membrane) run infero-posteriorly and are most active during expiration (to increase tonus of intercostal space). Interosseous portions act during forced expiration whilst interchondral portion act during active inspirationInnermost intercostals: essentially the deeper parts of the internals separated from them by the intercostal nerves and vessels. Occur laterallySubcostals: run in the same direction as the internals, but cross 2 or 3 spaces, lower spacesTransverse thoracic: run from sternum and xiphisternum transversely to lower ribsLevator costarum: from transverse processes to ribsDescribe the pattern of distribution of neurovascular structures in the thoracic wallEnter the most medial part of posterior intercostal spaceIntercostal (and collateral) nerve from anterior rami of T1-11, T12 is subcostal nerveRun between parietal pleura and internal intercostal membrane in the middle of the spaceNear the angle of ribs pass between internal and innermost intercostal musclesLocated in costal grooves on inferior border of the ribs with nerve inferior to artery inferior to veinCollateral branches arise here and run along superior border of rib, nerve superior to artery to veinVessels also have anterior supply and drainage (internal thoracic artery)Describe the arterial supply of the intercostal spacesPosterior intercostal arteries: Branches of the supreme/superior intercostal artery from the costocervical trunk of the subclavian -> 1 & 2, and of the thoracic aorta -> othersAnterior intercostal arteries: Branches of the internal thoracic -> spaces 1 to 6, musculophrenic artery -> spaces 7 to 9)The internal thoracic artery arises from the subclavian, passes inferiorly lateral to the sternum, between costal cartilages and transverse thoracic muscle, divides at 6th ICS into musculophrenic (lateral) and superior epigastric arteries2006-1What are the surface landmarks for the insertion of anterior and lateral intercostal tubesAnterior: 2nd intercostal space in the mid clavicular lineLateral: 4th or 5th intercostal space just anterior to the mid axillary lineWhat are the layers traversed when inserting through the lateral chest wall? 2006-1, 2007-1Skin & subcutaneous tissueLayers of muscle (3 layers), external, internal and innermost intercostalsParietal PleuraWhere do the intercostal vessels run?Under the rib aboveBetween the middle and innermost intercostal musclesThere is also collateral vessels at the lower section of the intercostal space2004-2Identify the major parts of this bone (Rib & Thoracic Vertebrae)What are the contents of the intercostal spaceThree layers of muscle, external, internal and innermostBetween middle & inner under rib above lies:VeinArteryNerve2010-1, 2007-1, 2005-2Bone: First RibWhat bone is this?First RibAppropriate sideWhat are the bony landmarks?Head (with single facet for T1)NeckTubercle for transverse process of T1Superior surface, lateral to medialGroove for subclavian arteryScalene tubercle and ridgeGroove for subclavian veinCostal grooveWhat muscles attach to this bone?Anterior scalene (tubercle)Middle scalene (medial to groove for artery)IntercostalsSerratus anteriorSubclavius (at costochondral junction)Longissimus portion of erector spinae attaches between tubercle and angle2007-1, 2005-2What are the neurovascular relations of this bone?NervesC8-T1 above and below neckSympathetic trunk in contact with neck next to headUnderneath the first intercostal neurovascular bundleIn groove for subclavian artery is lower trunk of brachial plexusVesselsSubclavian artery touching outer border of ribSubclavian veinUnder is the costal groove is the neurovascular bundle of first intercostal spaceOtherThe cervical pleural and apex of lung2010-2, 2009-2, 2005-1 (CXR)Describe the surface anatomy of the parietal pleura.Posteriorly Small section medially are inferior to the 12th rib Parallel to vertebral column to T1Cupola rises 2-3 cm above medial 1/3 of clavicle to the level neck of the 1st rib (but not above it)What is the clinical significance of the attachment of the pleura? 2010-2Cervical pleura may be injured, e.g. subclavian or IJ line insertion or penetrating injury to neckDeviation of pleura to the left provides a window for pericardiocentesis without traversing the pleuraThe attachment of the pleura at a lower level than the lungs (posterolaterally) favours collection of pleural fluid in this area (drainage, clinical findings)Penetrating injuries to the upper lumbar region (Mnemonic: 2-4-6-8MCL-10MAL-12PAL)2009-2How does surface anatomy of the lung compare to that of the pleura?Assuming quiet respiration…Lungs: 2 ribs higher below the 6th rib/at MAL and posteriorlyThe costodiaphragmatic recesses are not occupied by lung and thus fluid will accumulate here2010-2, 2008-2, 2008-1, 2007-1, 2005-2, 2004-2 (great vessels and ligamentum arteriosum)Model of Heart (Somso HS1)Identify the chambers and valves of the heart on this modelDemonstrate the chambers of the heart and their borders 2008-1Atria are separated from the ventricles externally by the coronary sulcus (AV groove)Internally by the fibrous skeleton (rings and trigone) that provides attachments and insulatesLeft and right ventricles demarcated by the anterior and posterior interventricular (IV) sulciThe crux is where the coronary sulcus and posterior IV sulci meetDemonstrate where the major components of the conducting system would be foundSA-node: Ant-lat near junc of SVC and RA AV-node: Post-inf interatrial septum near coronary sinus opening AV bundle of His: via the fibrous skeleton of the heart, along the membranous part of the inter-ventricular septumRight and left bundles: pass on each side of the muscular IV septum2005-2Identify the structural components of the tricuspid valve.3 cusps (ant, post and septal attached to fibrous A-V ring)Chordae tendinaePapillary musclesIdentify the main features of the right atriumPOINTS REQUIREDSVCIVCAuricleCoronary sinusFossa ovalis (remnant of foramen ovale)Identify the Ligamentum Arteriosum What is the role of the ductus arteriosus in the foetus?POINTS REQUIRED1 Bypasses Lungs – deoxygenated blood from head – BCVs – RA – RV – Pulmonary Trunk – DA – Aorta – Umbilical Artery - Placenta – Reoxygenated2010-1, 2008-1, 2007-1, 2006-1Using this model, describe the arterial supply of the heartMain coronary vessels arise from corresponding aortic sinus above aortic valveRCA in (R)AV groove gives off:SA nodal to supply SAN (in 60%)(R) atrial(R) marginalPost interventricular (in 2/3) which supplies post 1/3 of IV septumAV nodal (in 80%)Supplies: RA, most of RV, inferior surface of heart (diaphragmatic part of LV), post 1/3 septum, and more commonly the SA (60%) and AV (80%) nodesLCA in (L)AV groove bifurcates:CircumflexLAD (anterior I-V artery) to supply the ant 2/3 of IV septumCirc gives off left marginal branchLAD gives off lateral diagonalSupplies: LA, most of LV, ant 2/3 IV septum (more of His and Purkinje), less commonly the SA or AV nodesDemonstrate the venous drainage of the heartMajor drainage is via the Coronary sinus3 main tributaries areGreat cardiac vein (accompanies LAD, then Circ)Middle cardiac vein (accompanies PIV)Small cardiac veins (accompanies R marginal)Oblique vein (L) atrium marks start of sinusAnt cardiac veins start ant surface RV, drain straight into RASmallest cardiac veins (venae cordis minimae, Thesbian veins) drain direct into chambers2006-1Describe the arterial supply to the cardiac conduction systemSA node: RCA 60%, LCA via Circumflex 40%AV Node: RCA 80%AV bundle of His Purkinje fibres – LCA via LAD2011-1, 2009-2, 2009-1, 2007-2, 2006-2, 2004-2 (great vessels on model), 2003-2Photo: Thoracic inlet.?Major vessels and relationshipsIdentify the vascular structures in this photo (pg 210)Veins: Arteries:Superior vena cava (26) Brachiocephalic trunk (4) Thyrocervical trunk (32):L (13) and R (18) brachiocephalic v.Right common carotid a. (19) Inferior thyroid art. (6)Left and right subclavian v. (24) Left common carotid a. (14) -> Ascending cervical art (3)Left internal jugular vein (8) Right subclavian artery (21)Transverse -> Superficial cervical a. (25)Inferior thyroid veins (7)Internal thoracic a. (9)Suprascapular a. (27)Nerves: Upper trunk BP (35), phrenic (17), vagus (R=22, L=15), right recurrent laryngeal (20)Others: Thyroid (12), cricoid (2), trachea (33), thymus (31), parietal pleura (16)What are the posterior relations of the thyroid gland? 2009-2Cricothyroid membrane, trachea, right and left common carotid arteries laterallyDescribe the course of the right subclavian artery 2009-1, 2005-1Arises from brachiocephalic trunkRuns posterior to right sternoclavicular joint as ascends through thoracic inlet Arches superolaterally and passes posterior to anterior scalene muscleRelationship to this muscle defines its 3 partsDescends posterior to middle of clavicle and crosses over 1st rib to become axillary arteryName the branches of the subclavian artery1st PartVerterbral arteryInternal thoracic aThyrocervical trunk2nd PartCostocervical trunk3rd PartDorsal scapular(Mnemonic: Vit C&D, and Tits for thyrocervical)2006-2Name branches of the thyrocervical trunkInferior thyroid a.Transverse cervical a. (-> superficial +/- dorsal scapular a)Suprascapular a.2007-2Describe the branches of the descending thoracic aortaPosterior intercostal arteries, paired x9, run laterallyBronchial, 1-2 branches, usually paired laterallyMedisatinalOesophageal, unpaired 4-5 branches anteriorlySubcostalSuperior phrenicSubphrenic ................
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