18.10.2011

1. 18.10.2011 Kaan Yücel M.D., Ph.D.

2. DIAPHRAGM • A verythin, a double-domedmuscle, is theonlystructure (apart fromthepleuraandperitoneum) thatseparatesthechestfromtheabdominalviscera • Itsmainlyconvexsuperiorsurfacefacesthethoraciccavity, anditsconcaveinferiorsurfacefacestheabdominalcavity.

4. The diaphragm is the chief muscle of inspiration (actually, of respiration altogether, because expiration is largely passive). • It descends during inspiration; however, only its central part moves.

5. Thecentraltendon of thediaphragmis a thin but strongaponeurosissituatednearthecenter of thevaultformedbythemuscle.

6. Duringexpiration, therightdomereaches as high as the 5th ribandtheleftdomeascendstothe 5th intercostalspace. Thelevel of thedomes of thediaphragmvariesaccordingtothe: • Phase of respiration (inspirationorexpiration) • Posture(e.g., supineorstanding) • Size anddegree of distension of theabdominalviscera.

7. It is dividedintothreeparts, based on theperipheralattachments: • Sternalpart • Costalpart • Lumbarpart

8. Thecrura of thediaphragmaremusculotendinousbandsthatarisefromtheanteriorsurfaces of thebodies of thesuperior3 lumbarvertebrae, theanteriorlongitudinalligament, andthe IV discs. Leftcrus Right crus

9. Therightandleftcruraandthefibrousmedianarcuateligament, whichunitesthem as it archesovertheanterioraspect of the aorta, form theaortichiatus. Thediaphragm is alsoattached on eachsidetothemedialandlateralarcuateligaments.

10. Arteries Thearteriessupplyingthethediaphragmarethebranches of theinternalthoracicartery, thethoracic aorta andtheabdominalaorta.

12. Veins Theveinsemptyintotheinternalthoracicveinsandtheinferiorphrenicveins. Lympathicdrainage of diaphragm Lymphfromthenodes of thediaphragmdrainsintotheparasternal, posteriormediastinal, phrenic, anteriordiaphragmatic, andsuperiorlumbar (caval/aortic) lymphnodes. Innvervation Theentire motor supplytothediaphragm is fromtherightandleftphrenicnerves.

13. Phrenicnerve

14. DiaphragmaticApertures Thediaphragmaticapertures (openings, hiatus) permitstructures (vessels, nerves, andlymphatics) topassbetweenthethoraxand abdomen. Therearethreelargeaperturesfor: Inferior vena cava (IVC) Esophagus Aorta anda number of smallones. I’m EatingApples.

15. Themostsuperior of thethreelargediaphragmaticapertures • An aperture in thecentraltendonprimarilyfortheIVC • Alsopassingthroughthecavalopening: • terminal branches of therightphrenicnerveand a fewlymphaticvessels. CAVAL OPENING

17. ESOPHAGEAL HIATUS • An oval openingfortheesophagus in themuscle of therightcrus of thediaphragm at thelevel of the T10 vertebra. • Alsotransmitstheanteriorandposteriorvagaltrunks, esophagealbranches of theleftgastricvessels, and a fewlymphaticvessels.

19. VentricularSeptalDefects (VSD): Themembranouspartof theIVS is thecommon site of ventricularseptaldefects (VSDs) , althoughdefectsalsooccur in themuscularpart. • VSDsrankfirst on alllists of cardiacdefects. • A VSD causes a lefttorightshunt of bloodthroughthedefect. • A largeshuntincreasespulmonarybloodflow, whichcauses severe pulmonarydiseaseandmaycausecardiacfailure. Clinical Notes- VENTRICLES

21. AtrialSeptalDefects (ASD): A congenitalanomaly of theinteratrialseptum, usuallyincompleteclosure of the oval foramen, is an atrialseptaldefect (ASD). • LargeASDsallowoxygenatedbloodfromthelungsto be shuntedfromtheleftatriumthroughthe ASD intotherightatrium, causingenlargement of therightatriumandventricleanddilation of thepulmonarytrunk. • Thislefttorightshunt of bloodoverloadsthepulmonaryvascularsystem, resulting in hypertrophy of therightatriumandventricleandpulmonaryarteries. Clinical Notes- ATRIA

23. Clinical Notes- valves Disorders involving the valves of the heart disturb the pumping efficiency of the heart. Valvular heart disease produces either stenosis (narrowing) or insufficiency. Becausevalvulardiseasesaremechanicalproblems, damagedordefectivecardiacvalves can be replacedsurgically in a procedurecalledvalvuloplasty. Stenosis is the failure of a valve to open fully, slowing blood flow from a chamber.

24. Clinical Notes- valves Insufficiency or regurgitationis failure of the valve to close completely, usually owing to nodule formation on the cusps so that the edges do not meet or align. This allows a variable amount of blood to flow back into the chamber it was just ejected from. Both stenosis and insufficiency result in an increased workload for the heart.

25. Clinical Notes- valves Mitral Valve Insufficiency (Mitral Valve Prolapse): Scarring and shortening of the cusps results in insufficiency Restricts the outflow of the left ventricle and leads to the hypertrophyof themyocardium During ventricular systole, blood regurgitates back to the left atrium A hurt murmur will be heard.

26. Clinical Notes- valves Mitral valvestenosis Narrowing of the mitral orifice Restricts the outflow of the left atrium A murmur will be heard during atrial contraction

27. Clinical Notes- valves Pulmonary valve stenosis Narrowing of the pulmonary valve due to the fused cusps Restricts the outflow of the right ventricle and leads to the hypertrophy of the myocardium.

28. Clinical Notes- valves • Pulmonary valve incompetence • Incomplete closure of the cusps due to thickening of their free margins due to a disease • During diastole, blood regurgitates back to the right ventricle fromthe pulmonary trunk • Heart murmur (a pathologic sound) could be heard by stethescope. Murmur is produced due to the turbulancecaused by the bloodpassing from a narrow opening into a larger vessel or chamber.

29. Clinical Notes- valves Aortic insufficiency During diastole blood regurgitates from aorta back to the left ventricle. A hurt murmur will be heard during diastole.

30. Clinical Notes- valves Aortic Valve Stenosis The most frequent valve abnormality. (MVP??) Blood is unabletoflowfreelyfromleftventricleto aorta. The great majority of aortic stenoses is a result of degenerative calcification, and fusion of the aortic cups as a result. Aortic stenosis causes extra work for the heart, resulting in left ventricular hypertrophy.