Dissection of pericardium and heart in situ

Conduction system of heart.

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Image #117-5
Bassett ImageDiagram Image
Legend Image
Dissection of pericardium and heart in situ
Conduction system of heart.
The sinoatrial node (4) has been exposed by removal of the epicardium near the junction of the superior vena cava and the right atrium. The atrioventricular node (16) has been exposed by the removal of endocardium and some atrial myocardium just above the entrance of the coronary sinus into the right atrium. The atrioventricular bundle has been dissected in its course into the membranous atrioventricular septum, and its right branch (15) has been uncovered by the removal of endocardium and a portion of the myocardium of the muscular interventricular septum. A segment of the septal cusp of the tricuspid valve has also been cut away.
1 . Ascending aorta
2 . Reflection of pericardium onto superior vena cava
3 . Right coronary artery (cut off)
4 . Sinoatrial node
5 . Upper pointer: Interventricular septum (membranous part) Lower pointer: Right fibrous trigone (exposed by removal of atrial myocardium)
6 . Border of fossa ovalis
7 . Fossa ovalis
8 . Myocardium of right atrium (left pointer indicates position of a delicate tendon which extends from the right fibrous trigone toward the border of fossa ovalis)
9 . Upper pointer: Latex cast in coronary sinus Lower pointer: Valve of coronary sinus
10 . Valve of inferior vena cava
11 . Latex cast in inferior vena cava
12 . Septal (medial) cusp of tricuspid valve
13 . Pulmonary trunk
14 . Valve of pulmonary trunk (pointer on left semilunar cusp)
15 . Right crus atrioventricular bundle
16 . Atrioventricular node (no distinct boundary found between node and myocardium inferior to it)
17 . Septomarginal trabecula (moderator band)
18 . Anterior papillary muscle
19 . Right ventricle