HEART & RIGHT ATRIUM - Hardik Saini.pptx

heart and right atrium anatomy

1. Heart Submitted By :- Hardik Saini

2. Heart is a conical , hollow , muscular organ. Lies in middle mediastinum. Heart is placed obliquely behind the body of sternum & adjoining part of costal cartilage. 1/3 rd of it lies to right and 2/3 rd of it lies to left. The direction of blood flow from atria to ventricle is downward , forward and lateral. Measurement of heart :- length= 12cm Thickness= 9cm Weight :- in Males= 300g in females= 250g

3. Surrounded by fibro-serous sac called PERICARDIUM.

4. External Features Human heart has 4 chambers :- right and left atria & ventricle The atria lies above and behind the ventricle. On the surface of heart , atria are separated from ventricle by Atrio -ventricular groove . Inter-atrial groove :- present between two atria. Inter-ventricular groove :- present between two ventricle. These grooves are subdivided into anterior and posterior part.

5. The Heart has :- Apex ( directed downward , forward & left ) Base (posterior surface directed backward ) Surfaces :- Anterior :- sternocostal Inferior :- diaphragmatic Left Lateral Borders :- upper border inferior border right border left border

6. Grooves and sulci Atria are separated from ventricle by atrioventricular groove (coronary sulcus) , divided into anterior and posterior part. Anterior part also consist of right and left half. Right half is between right auricle and right ventricle lodging right coronary artery. Left half is small between left auricle and let ventricle , lodges circumflex branch of left coronary artery. Coronary sulcus is overlapped anteriorly by ascending aorta & pulmonary trunk. The anterior interventricular groove is near to left margin of heart and posterior interventricular groove on diaphragmatic or inferior surface.

7. Apex Formed by left ventricle. Directed downward , forward & left. Overlapped by anterior border of left lung. Situated in the left 5 th intercostal space 9cm lateral from midsternal line. Base Also called the posterior surface. Formed mainly by left atrium and small part by right atrium. Relation :- 4 pulmonary veins open into left atrium. superior and inferior vena cava open into right atrium.

8. BORDERS OF HEART UPPER BORDER :- - slightly oblique. -formed by two atria , chiefly by right atria. 2. RIGHT BORDER :- -vertical and formed by right atrium. -extends from superior to inferior vena cava.

9. 3. INFERIOR BORDER :- -Nearly horizontal. -formed mainly by right ventricle & partly by left ventricle. -extend from inferior vena cava to apex. 4.LEFT BORDER :- -oblique and curved. -formed mainly by left ventricle and partly by left auricle. -extends from apex to left auricle. -separates anterior &left surface of heart.

10. SURFACES OF HEART ANTERIOR OR STERNOCOSTAL SURFACE Formed mainly by right atrium , right ventricle & partly by left ventricle and left auricle. Most of the sternocostal surface is covered by lung but a part of it that lies behind the cardiac notch of left lung is uncovered. The uncovered area is dull of percussion and called area of superficial cardiac dullness.

11. 2. INFERIOR OR DIAPHRAGMATIC SURFACE Rest on the central tendon of diaphragm. Left 2/3 rd part is formed by left ventricle and 1/3 rd part is formed by right ventricle. 3. LEFT LATERAL SURFACE Formed mainly by left ventricle and upper end of left auricle. In the upper surface , the surface is crossed by the coronary sulcus and it is related to left phrenic nerve , left pericardicophrenic vessels and pericardium.

12. Crux of the heart The meeting point of inter-atrial , atrioventricular & posterior inter-ventricular groove.

13. RIGHT ATRIUM Position :- right upper chamber of heart. It form :- Right border part of upper border sternocostal surface base of heart Function :- receives venous blood (deoxygenated) from complete body (by superior and inferior vena cava). pump deoxygenated blood to right ventricle through tricuspid valve or right atrioventricular orifice.

14. External Features Chamber is vertically elongated , receiving blood from superior vena cava at upper end & inferior vena cava at lower end. Upper end is prolong to the left forming right auricle. Right auricle :- covers root of ascending aorta. partly overlap infundibulum of right ventricle. interior is sponge-like which prevents free flow of blood. Along the right border of right atrium a shallow vertical groove is present from superior to inferior vena cava is called as sulcus terminalis. Sulcus terminalis is produced by an internal muscular ridge called crista terminalis.

15. Upper part of sulcus contains SA node which acts as pacemaker of heart. Right atrioventricular groove separates the right atrium from right ventricle. Right atrioventricular groove lodges right coronary artery and small cardiac vein. Tributaries or inlets of right atrium :- Superior vena cava Inferior vena cava Coronary sinus Anterior cardiac vein Venae cordis minimae Right marginal vein

16. Right atrioventricular orifice (tricuspid valve) Blood passes out of right atrium through right atrioventricular orifice by tricuspid valve and goes to right ventricle. The tricuspid orifice is guarded by the tricuspid valve which prevents backflow of blood.

17. Internal features Smooth posterior part ( sinus venerum ) Rough anterior part ( pectinate part ) Interatrial septum

18. Smooth posterior part ( sinus venerum ) Derived from right horn of sinus venousus. Most of the tributaries open into posterior wall except Anterior Cardiac vein. superior vena cava :- upper end of posterior wall of right atrium. inferior vena cava :- lower end of posterior wall of right atrium. - opening of inferior vena cava is guarded by a rudimentary valve :- Eustachian valve - during embryonic life valve guides the inferior vena cava blood to left atrium through foramen ovale.

19. Coronary sinus opens between opening of inferior vena cava & right atrioventricular orifice. Venae cordis minimae :- these are small numerous veins present in the wall of all the four chambers , they open into right atrium through small foramina. Intervenous tubercle (tubercle of lower) :- it is a very small projection difficultly visible on the posterior wall of atrium just below the opening of superior vena cava. during embryonic life , it directs superior vena cava blood to right ventricle.

20. Rough anterior part ( pectinate part ) Derived from primitive atrial chamber. A series of transverse muscular ridges are present i.e. called musculi pectinati . Musculi pectinati arise from crista terminalis , runs forward & downward towards atrioventricular orifice giving appearance of teeth of a comb. In the auricle muscles are interconnected to form a reticular network.

21. Interatrial septum Derived from septum primum & septum secondum. A shallow saucer shaped depression is present in lower part is called Fossa Ovalis . Fossa Ovalis represents the site of embryonic Septum Primum. Annulus Ovalis (Limbus fossa ovalis) is the prominent margin of fossa ovalis. It represents lower edge of septum secondum. Remnant of Foramen Ovale are occasionally present. Small slit like vascular opening between upper part of fossa & limbus is normally occluded after birth but may persist sometimes.

22. Clinical anatomy •Thrombosis of coronary artery is a common cause of sudden death in persons past middle age. This is due to myocardial ischaemia infarction and ventricular fibrillation. •Incomplete obstruction, usually due to spasm of the coronary artery causes angina pectoris, which is associated with agonizing pain in the precordial region and down the medial side of the left arm and forearm.

23. •Coronary angiography determines the site of narrowing or occlusion of the coronary arteries or their branches. •Angioplasty helps in removal of small blockage. It is done using small stent or small inflated balloon through a catheter passed upwards through femoral artery, aorta, into the coronary artery. •If there are large segments or multiple sites of blockage, coronary bypass is done using either great saphenous vein or internal thoracic artery as graft.

24. Previous Year Questions Q-1. Describe the external features and blood supply of heart ? Q-2. Describe the right coronary artery giving its origin, course, branches, area of distribution and applied anatomy ? Q-3. Describe the interior of right atrium ? Q-4. Describe right atrium and give its tributaries & applied importance ?