The purpose of this blood serum test is to help detect and evaluate treatment of acute hepatic disease, especially hepatitis, and cirrhosis without jaundice. To help distinguish between mytyocardial (heart) and liver tissue damage (used with the AST enzyme test). Also to assess hepatotoxicity of some drugs.
The average wingspan for an NBA player (even normal 6'0 guys) is +4 inches. I think that around your height thing is just an estimate. For the general population, the average might be +2 inches.
Robert welcome to the forum. I' m not much of a game person, so what I'm offering is just a guess. Lines C & E' would form the crosshairs. The numbers on A is range estimation for an average height say 5'10 for a man or 18 from brisket to back on certain game animals. You'd put the long horizonral line at the base of what you are ranging and the short horizontal line at the top.