| Ao | orifice area |
|---|---|
| AVO | aortic valve opening; aortic valve orifice; atrioventricular opening |
| CAVO | common atrioventricular orifice |
| EOA | effective orifice area; erosive osteoarthritis; esophageal obturator airway; examination, opinion, a... |
| LUO | left ureteral orifice |