| MAR | main admissions room; marasmus; marrow; maximal aggregation ratio; medication administration record;... |
|---|---|
| MER | mean ejection rate; medical emergency room; methanol extraction residue; murmur/energy ratio |
| OOR | out-of-room |
| OR | a logical binary relation that is true if any argument is true, and false otherwise; [o]estrogen rec... |
| ORN | operating room nurse; orthopedic nurse |
| posterior ethmoidal air cells | The posterior group of air cells of the ethmoidal sinus's; each sinus communicates with the superior meatus of the nasal cavity. Synonym: sinus ethmoidales posteriores, cellulae posteriores, posterior cells. (05 Mar 2000) |
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| supplemental air | The extra volume of air that can be expired with maximum effort beyond the level reached at the end of a normal, quiet expiration. Common abbreviation is erv. (12 Dec 1998) |
| tidal air | The volume of air inspired or expired during each normal, quiet respiratory cycle. Common abbreviations are tv or v with subscript t. (12 Dec 1998) |
| embolism, air | Embolism due to air bubbles entering the blood vessels after trauma, surgical procedures, or changes in atmospheric pressure. (12 Dec 1998) |
| tubal air cells | Occasional small air cells in the inferior wall of the auditory tube, near the tympanic orifice, communicating with the tympanic cavity. Synonym: cellulae pneumaticae tubae auditivae, air cells of auditory tube. (05 Mar 2000) |
| ethmoid air cells | The numerous small air-filled cells of the ethmoidal labyrinth. See: anterior ethmoidal air cells, middle ethmoidal air cells, posterior ethmoidal air cells. Synonym: cellulae ethmoidales, sinus ethmoidales, ethmoidal cells. (05 Mar 2000) |
| tympanic air cells | Numerous groovelike depressions in the walls of the tympanic cavity, communicating with the tubal air cells. Synonym: cellulae tympanicae, tympanic cells. (05 Mar 2000) |
| laminar air flow unit | An air-filtering system used at some transplant facilities to remove particulate matter and fungi from the air. (16 Dec 1997) |
| functional residual air | The volume of air remaining in the lungs at the end of a normal, quiet expiration. It is the sum of the residual volume and the expiratory reserve volume. Common abbreviation is frc. (12 Dec 1998) |
| liquid air | Air that, by means of intense cold and pressure, has been liquefied. (05 Mar 2000) |