| valve of coronary sinus | A delicate fold of endocardium at the opening of the coronary sinus into the right atrium. Synonym: valvula sinus coronarii, coronary valve, thebesian valve. (05 Mar 2000) |
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| coronary sinus | A short trunk receiving most of the cardiac veins, beginning at the junction of the great cardiac vein and the oblique vein of the left atrium, running in the posterior part of the coronary sulcus and emptying into the right atrium between the inferior vena cava and the atrioventricular orifice. Synonym: sinus coronarius. (05 Mar 2000) |
| coronary sinus rhythm | An ectopic atrial rhythm supposedly originating from a pacemaker at the mouth of the coronary sinus; recognised in the electrocardiogram by P-waves that are inverted in leads II, III, and a VI with a normal or prolonged P-R interval; an ectopic ("lower") atrial rhythm. (05 Mar 2000) |
| unroofed coronary sinus syndrome | <syndrome> A spectrum of cardiac anomalies in which part or all of the common wall between the coronary sinus and the left atrium is absent. (05 Mar 2000) |
| anal orifice | <anatomy> The distal or terminal orifice of the alimentary canal. (18 Nov 1997) |
| aortic orifice | The opening from the left ventricle into the ascending aorta; it is guarded by the aortic valve. Synonym: ostium aortae, aortic ostium. (05 Mar 2000) |
| cardiac orifice | The trumpet-shaped opening of the oesophagus into the stomach. Synonym: ostium cardiacum, cardiac opening, oesophagogastric orifice. (05 Mar 2000) |
| vaginal orifice | The narrowest portion of the canal, in the floor of the vestibule posterior to the urethral orifice. Synonym: ostium vaginae, orificium vaginae, vaginal opening. (05 Mar 2000) |
| gastroduodenal orifice | The opening between the stomach and the superior part of the duodenum. Synonym: ostium pyloricum, gastroduodenal orifice. (05 Mar 2000) |
| golf-hole ureteral orifice | A retracted funnel-shaped condition of the ureteral orifice in the wall of the bladder, due often to tuberculosis or a secondary sclerosis of the ureter. (05 Mar 2000) |
| root canal orifice | An opening in the pulp chamber leading to the root canal. (05 Mar 2000) |
| mitral orifice | An atrioventricular opening which leads from the left atrium into the left ventricle of the heart. Synonym: ostium atrioventriculare sinistrum, ostium arteriosum. (05 Mar 2000) |
| pulmonary orifice | The opening of the pulmonary trunk from the right ventricle, guarded by the pulmonary valve. Synonym: ostium trunci pulmonalis, pulmonary orifice. (05 Mar 2000) |
| pyloric orifice | The opening between the stomach and the superior part of the duodenum. Synonym: ostium pyloricum, gastroduodenal orifice. (05 Mar 2000) |
| ileocaecal orifice | The opening of the terminal ileum into the large intestine at the transition between the caecum and the ascending colon. Synonym: ostium ileocaecale, ileocaecal opening. (05 Mar 2000) |