anal fistula (fistula in aÂ´no) one opening on the cutaneous surface near the anus, which may or may not communicate with the rectum. arteriovenous fistula one between an artery and a vein, either pathologic (such as a varicose aneurysm) or surgically created to ensure an access site for hemodialysis.
1 millibar (or hectopascal/hPa), is equivalent to 0.02953 inches of mercury (Hg). It is therefore only necessary to multiply a reading in millibars by the latter figure, to achieve the required conversion. E.g. for 1023 mbar, multiply by 0.02953=30.21 inches.
Inches of Mercury. (or in Hg) Unit of atmospheric pressure used in the United States. The name comes from the use of mercurial barometers which equate the height of a column of mercury with air pressure. One inch of mercury is equivalent to 33.86 millibars or 25.40 millimeters. See barometric pressure. First divised in 1644 by Evangelista Torricelli (1608-1647), an Italian physicist and mathematician, to explain the fundamental principles of hydromechanics.