Sinoatrial nodal artery variant in approximately 10% of human hearts. This artery is larger than normal and supplies a good part of the left atrium, but also right sided structures like part of the sinoatrial node and the atrioventricular nodal areas. In this variant, the artery courses in the sulcus between the left superior pulmonary vein and the left atrial appendage where it could be susceptible to injury during catheter or surgical ablation procedures on the left atrium, especially for atrial fibrillation ablation or open heart cardiac surgery. Sinoatrial nodal artery The sinoatrial nodal artery (or sinuatrial nodal artery or sinoatrial artery) is
Sentinel node list, can be simplified remarkably using a sentinel node to demarcate the beginning and end of the list. Following is a Python implementation of a circular doubly-linked list: Notice how the codice_13 method takes the node that will be displaced by the new node in the parameter codice_14. For appending to the left, this is the head of a non-empty list, while for appending to right, it is the tail. But because of how the linkage is setup to refer back to the sentinel, the code just works for empty lists as well, where codice_14 will be the sentinel node.